Author Topic: Gen V 454 into 88 V20 burb  (Read 10995 times)

Offline MuddiGGEr25

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Gen V 454 into 88 V20 burb
« on: March 21, 2017, 07:29:45 PM »
I have already done some searching and the overall consensus is that the TBI 454 was just junk because of the small rectangle "peanut" port heads. I have been on jegs and summit and it seems that the cheapest cast iron replacements are about $600/ each and thats a bit outside my budget for now, just curious if an older set of big block heads would be able to bolt on or not, as i can get various used ones from mudding buddies that swap parts around between events for a good price.

Speaking of price its in a running 1995 pickup, can hear it run before it gets pulled, $350 for engine, harness and PCM. Im not entirely sure how its gonna like the TH400 but i can deal with that later or just see about the TBI to carb adapter.

I have read that CAI, and good exhaust headers help it breathe a little better, i can do that, and ive seen a dyno chart with a towmaster chip that helped somewhat but he couldnt get a good read at lower RPM so that doesnt help me much, gear vendors had the following chart on thier website for the L19: http://www.gearvendors.com/wp-content/uploads/2015/11/gm74.gif

Now i have read and heard several accounts that the 94-95 3/4 and 1ton 454 and SS trucks were higher flowing injectors @ 28-32and a different ?PCM? gaining approx 20ft-lbs,  I am ok with the heads being done with flow by 3500 RPM as this is not gonna be a drag truck or anything of the sort, its gonna be a 3/4 ton grocery getter and DD for work. occasionally pulling a trailer ranging 5K-9K usually empty though and a 3 mile drive to work, i spend all my time under 3000RPM anyway with the 6.2l detroit i have now.

Is there any reason it wont work? (not should i or should i not) i mean is there some physical limitation that will not allow me to put it in?

I know that i can change the cam/lifters/rods and gain a safe 70-100ft-lbs across the board, but not sure what the PCM is going to be ok with as far as specs for lift/duration, i know the cam in my 1987 L05 TBI 350 isnt really computer friendly because it tries to kill itself if i allow it to go into closed loop while cruising, but runs good (just alittle lean) in open loop all the way to 6000rpm, BUT my 350 TBI heads limit my power to about 3800-4200 and the rest is all noise up to 6K when it wont turn any faster

Im just thinking that the 1994-1995 405ft-lb rating at 4000, is 100-150 more than the 6.2L i currently have and should be a big step up,even at lower RPM, I have a lunati "Thumpr" cam for a GenIV i think, but i dont think its compatible IIRC.
1988 V10 Suburban 5.7L TBI/TH350 39K on rebuild 4.10AR GM14FF/GM10SF 235/85R16 & 18.4-16.1

1988 V20 Suburban 6.2L-J/TH400 CA truck, 125K G80 14FF/ GM10 4.10AR GVWR 8,600

1977 Ford Granada ~450HP 302 2bbl/C4 27K original 2.47 215/70R14

Offline Rattler12

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Re: Gen V 454 into 88 V20 burb
« Reply #1 on: March 22, 2017, 08:24:32 AM »
If you're going to stay below 3000 rpm keep the peanut port heads. They make better low end torque than oval or square port heads. Get a good "tow" cam . Don't go radical with duration and lift. Increased port size, duration, lift and decreased lobe separation angel = higher rpm to get the benefit and will be counter productive to what you say your use will be....jm2c's
Physically it will bolt right in with a change of motor mounts.
83 C-10 shorty 454, 5spd, 3:73 posi

Offline big_al273

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Re: Gen V 454 into 88 V20 burb
« Reply #2 on: March 22, 2017, 01:59:15 PM »
I would avoid a Gen V 454 (1991-1995) and look for a Mark VI 454 instead. The Gen V has many small differences from the mark IV making many parts incompatible between generations, this combined with a smaller aftermarket selection for the Gen V make the Mark IV a superior choice for building or upgrading in my opinion.
http://www.superchevy.com/how-to/4567-chevrolet-big-block-engine-generations/
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Offline MuddiGGEr25

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Re: Gen V 454 into 88 V20 burb
« Reply #3 on: March 22, 2017, 03:47:55 PM »
If you're going to stay below 3000 rpm keep the peanut port heads. They make better low end torque than oval or square port heads. Get a good "tow" cam . Don't go radical with duration and lift. Increased port size, duration, lift and decreased lobe separation angel = higher rpm to get the benefit and will be counter productive to what you say your use will be....jm2c's
Physically it will bolt right in with a change of motor mounts.

I will definitely be staying under 3000RPM except maybe on the highway bc with my 4.10 gears and 265/75R16 im turning about 2500rpm at 60MPH, which is fine for me, and if im in a hurry and want to drive the speed limit its about 3200rpm @75 and i really dont wanna go faster in this ol brick


I would avoid a Gen V 454 (1991-1995) and look for a Mark VI 454 instead. The Gen V has many small differences from the mark IV making many parts incompatible between generations, this combined with a smaller aftermarket selection for the Gen V make the Mark IV a superior choice for building or upgrading in my opinion.
http://www.superchevy.com/how-to/4567-chevrolet-big-block-engine-generations/

I will read up on that, but gen VI are very rare to come by and the ones ive seen they want $1000+ just for the engine and $200 for the wires and PCM, or $3000+ for the whole truck even if its rusted all to heck, and people with GenIV list em around $500-$800 up this way unless its bone stock and they have no idea if and when it ran last, but most i see are bought up right away for mud trucks so theres that too. this one wasnt really advertised he just said he has a ton of trucks he bought for parts and i askedhim if he had a 454 and if so how much.  Im not worried about backwards compatibility, i was just curious if i could cheap and swap older heads on and save myself $1200-$2000.  Im sure the newer ones are superior in most if not all aspects OEM for OEM.







___________________________________________________________________________________________________________________________

Oh another note ive been reading up on here: http://tbichips.com/?page_id=87

and he recommended this cam after his experience with the 2 TBI 454's that he worked on https://www.summitracing.com/parts/sum-k1300 but thats a GEN-IV cam and requires some other parts too, and says its not computer friendly so ive been digging up in the pirate4x4 also and stumbled across this: http://www.pirate4x4.com/forum/tow-rigs-trailers/1848777-bbc-towing-cam-suggestions.html  and this is the cam COMP recommended with his towing in mind: https://www.summitracing.com/parts/cca-k11-302-4

According to COMP he(and i ) could see #'s close to 500Ft-lbs and one of the commentors seemed to agree....

Is there a better low end cam that anyone can remember off hand? i am planning on calling COMP later this week, when i have more time to see if they recommend any different, but my goal is to do what i can to help the heads breather better (cam and exhaust/CAI) for now, wait a month or two and swap the cast iron intake for the Edelbrock Performer 454 TBI Intake Manifolds 3764  https://www.summitracing.com/parts/edl-3764 as i have seen it mentioned atleast a dozen times and havent really read anything majorly negative about it.


My goal is to have good TQ by the time i get to 1800-2000RPM and keep a decently steady line across until i get to 3200 just in case i need to downshift for the bigger hills down south and be in 2nd @ 45-50 for a short while, id much rather have enough to just stay in 3rd but we all know thats not always possible if you get hit with a big headwind or dont get a good headstart on a mountain climb

I want to just keep the rest OEM/stock im not trying to make a speed demon and i wont need lots of HP, maybe my wife will take it in the mud to play once in a great while but shes nice on the throttle off road so redline isnt even in her vocab lol, unlike me in the mud toy i redline quite often
1988 V10 Suburban 5.7L TBI/TH350 39K on rebuild 4.10AR GM14FF/GM10SF 235/85R16 & 18.4-16.1

1988 V20 Suburban 6.2L-J/TH400 CA truck, 125K G80 14FF/ GM10 4.10AR GVWR 8,600

1977 Ford Granada ~450HP 302 2bbl/C4 27K original 2.47 215/70R14

Offline big_al273

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Re: Gen V 454 into 88 V20 burb
« Reply #4 on: March 22, 2017, 05:31:43 PM »
whoops just realized i wrote to look for a gen VI (6) when i meant a Mark IV (4). The Mark IVs are quite common (made from 1965-1990 from what i understand) and from 87-90 they were available with TBI, sorry about that mix up.
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Offline MuddiGGEr25

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Re: Gen V 454 into 88 V20 burb
« Reply #5 on: March 23, 2017, 06:57:06 AM »
whoops just realized i wrote to look for a gen VI (6) when i meant a Mark IV (4). The Mark IVs are quite common (made from 1965-1990 from what i understand) and from 87-90 they were available with TBI, sorry about that mix up.

so would i be able to utilize the 95 TBI system on a 87-90 block? it runs 28-32PSI instead of the standard 10-13PSI, or would i be able to put a TBI intake on a MARKIV or are there some holes that wont line up? i really like the idea of being able to start it remotely when its below 0F up here, i have a damaged vertebrae and arthritis spreading in my back, knees and hands, so by the time i make it all the way to the truck to start it, im already very very stiff and then have to walk all the way back while i wait for it to warm up. just like to avoid that if i can by using the TBI.
1988 V10 Suburban 5.7L TBI/TH350 39K on rebuild 4.10AR GM14FF/GM10SF 235/85R16 & 18.4-16.1

1988 V20 Suburban 6.2L-J/TH400 CA truck, 125K G80 14FF/ GM10 4.10AR GVWR 8,600

1977 Ford Granada ~450HP 302 2bbl/C4 27K original 2.47 215/70R14

Offline big_al273

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Re: Gen V 454 into 88 V20 burb
« Reply #6 on: March 23, 2017, 04:06:13 PM »
the 87-90 TBI 454 in the trucks was the same engine as 86 and earlier except they have an adapter plate/coolant heat exchanger between the intake and throttle body as well as the sensors for the computer, as for Gen V TBI, or possibly you mean TPI i don't really know much about it. If your just worried about starting the truck before you get to it there are many aftermarket remote start kits and provided the carb was setup right and used regularly i see no reason why they couldn't be used with a carb instead of TBI.
91 Chevy R3500 Crewcab future project
89 GMC R3500 Cab & Chassis Tool truck project
88 Chevy V30 Crewcab Ex-firetruck
87 Chevy R20 Crewcab future project
84 GMC K1500 winter beater

Offline MuddiGGEr25

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Re: Gen V 454 into 88 V20 burb
« Reply #7 on: March 26, 2017, 05:02:36 PM »
I have tried 2 different autostarts with a rebuilt Quadrajet with less than 3K miles on it, and had just passed CARB/SMOG check, so it was in optimal condition. i still had to pump the pedal a couple times to get it just enough to fire over. if the truck was warm (coolant temp guage 100F or higher) the auto start would usually do the trick, but it just doesnt work when its -20F or less outside and the fuel just evaporates up north here after not too long. even tried it with the 77 302 in my sig, runs like a champ and starts everytime with 2 pumps of the pedal even at -40F with no block heater. but the autostart has no way to pump the accel pump on either carb. if i could figure a way to shoot a little fuel right into the barrels it would probably work fine.


Its a good start from what ive been reading, the main complaints i have read over and over is the lack of power, mostly due to the tiny cam that GM put in it, i can swap the cam on a day off, and keep the stock exhaust, and keep the stock intake for the time being, which i know means i might not see the full potential of the cam replacement, but even if the cam just can make the most of the heads it came with that should be a good improvement over stock. fuel economy isnt really in my goals, if i can get near 7 in town, and 9 highway and stay above 6-7MPG towing the boat of a camper we just picked up then I will be fine with that.

I think the complaints about low MPG were also due to GM's cam choice because you had to push the engine harder to get any power out of it.

I attached a picture of the camper for reference, we towed it with the 6.2L this weekend with a 15MPH headwind the entire 176 miles home, and we maintained 45-50MPH and got 9-10mpg with the 6.2, but there was a lot of wind whipping through it with the original tip out design and i took the patio doors off so they wouldnt fall off on the highway.  the 6.2 could get up to 55 but 2 of the tires are still MH type and not the DOT i bought so i didnt want to push my luck, it was all flat land thankfully only a handful of small hills.
1988 V10 Suburban 5.7L TBI/TH350 39K on rebuild 4.10AR GM14FF/GM10SF 235/85R16 & 18.4-16.1

1988 V20 Suburban 6.2L-J/TH400 CA truck, 125K G80 14FF/ GM10 4.10AR GVWR 8,600

1977 Ford Granada ~450HP 302 2bbl/C4 27K original 2.47 215/70R14

Offline MuddiGGEr25

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Re: Gen V 454 into 88 V20 burb
« Reply #8 on: March 30, 2017, 12:12:27 PM »
UPDATE: going down to go pick it up, but also convinced him to sell me the trans with it, he said trans is in unknown condition as they never drove the truck, as it was only purchased for parts. So ive got a 50/50 choice of getting a good 4L80E with it also at only $100, so i figure if i only end up with a core then im about even, but im hoping to end up with a good engine/trans.


The 95 3/4ton has a mech T-case but he isnt sure which model, maybe NP241, but i think the 4L80E should mate up to my NP208, maybe need a VSS for the PCM, not sure on that model
OR my 88V10 dash has a VSS output using the speedocable for the TBI in that one, not sure if the 88V20 has the same circuit in it or not.

I will have to tap the PS return line for the hydroboost.

Does anyone have a link to the wiring diagrams for the 1995 454/4L80E so i can wire it right up to my existing dash/gauges.

Im reading some articles where people have replaced the TH400 or TH350 in square bodies with a 4L80e to see what else i will need or to buy
1988 V10 Suburban 5.7L TBI/TH350 39K on rebuild 4.10AR GM14FF/GM10SF 235/85R16 & 18.4-16.1

1988 V20 Suburban 6.2L-J/TH400 CA truck, 125K G80 14FF/ GM10 4.10AR GVWR 8,600

1977 Ford Granada ~450HP 302 2bbl/C4 27K original 2.47 215/70R14

Offline MuddiGGEr25

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Re: Gen V 454 into 88 V20 burb
« Reply #9 on: April 01, 2017, 12:48:13 AM »
Just wanted to check in before i head all the way to minneapolis in the morning to pick this up,

What i am buying:

TBI (32PSI version) 454 attached to a unknown 4L80E, harness and PCM, he also said he would grab the TCM if it is seperate, I wasnt sure on this one.

Its from a 1995 3/4 4x4 truck


I asked him to leave the stock exhaust manifolds and the Tcase adapter so that i can mate my NP208 to the 4L80E

I am not sure if it is coming with the airlceaner assembly, but i am already saving for a CAI anyway just because it might help when towing in the summer.

The engine will be complete with accesories oil pan to intake.

Is there anything else i should try to get while im there? i have a steering column with the P R N [D] D 2 L already, and i will have to get my rear driveshaft shortened 6-7" if i measured correctly, not sure about the front one yet but its probably gonna be too short
1988 V10 Suburban 5.7L TBI/TH350 39K on rebuild 4.10AR GM14FF/GM10SF 235/85R16 & 18.4-16.1

1988 V20 Suburban 6.2L-J/TH400 CA truck, 125K G80 14FF/ GM10 4.10AR GVWR 8,600

1977 Ford Granada ~450HP 302 2bbl/C4 27K original 2.47 215/70R14

Offline MuddiGGEr25

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Re: Gen V 454 into 88 V20 burb
« Reply #10 on: April 02, 2017, 10:52:27 PM »
well finally made it back, picture attached, she just barely fit behind that 3rd bench XD

quick list of what all i picked up today:

1995 454 TBI, (verified that the fuel pump was pushing 32PSI)
4L80E & OEM TC (pan is alot cleaner than the rest of the components so that might indicate it was pulled and inspected or rebuilt, but no clue, could have just been a filter change)
PCM w/ entire wiring harness + interior and exterior fuseblocks
front and rear driveshafts, just in case they were the right length after im all done with the swap.
A/C connection for the pump
Air cleaner assembly w/ reg filter


Im going to take a look and see if the VSS might be in the trans, but wondering if i will need to reprogram the PCM if my axle ratio is different.

Anyways its gonna be 2-4 weeks before i get to open er up and put the cam in and whatnot, but ill post updates as i figure stuff out or make progress


1988 V10 Suburban 5.7L TBI/TH350 39K on rebuild 4.10AR GM14FF/GM10SF 235/85R16 & 18.4-16.1

1988 V20 Suburban 6.2L-J/TH400 CA truck, 125K G80 14FF/ GM10 4.10AR GVWR 8,600

1977 Ford Granada ~450HP 302 2bbl/C4 27K original 2.47 215/70R14

Offline MuddiGGEr25

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Re: Gen V 454 into 88 V20 burb
« Reply #11 on: April 03, 2017, 12:43:48 AM »
I havent heard back from comp yet, but i did thier online CamShaft Breakdown tool, to see what the computer online would recommend and i got 2 recommendations for computer controlled:

1: 11-302-4
http://www.compperformancegroupstores.com/store/merchant.mvc?Screen=PROD&Store_Code=CC&Product_Code=11-302-4&Category_Code=MARKIVCAMHFTCC

2: 11-206-3
http://www.compperformancegroupstores.com/store/merchant.mvc?Screen=PROD&Store_Code=CC&Product_Code=11-206-3&Category_Code=MARKIVCAMHFTCC


When i was reading some threads most people agree that a wider LSA such as 112-116 agrees better with the TBI, but a 110 could be done.


Looking for opinions on these which one would be better at producing low end power, like i said above?

IIRC the sooner the intake opens and close the better for building low end power but i could be mistaken.


in OD i would be at 1900 @ 60MPH and in D(3) would be about 2600 @ 60MPH with 4.10 gears and 265/75R16, only very rarely would i need to be going 75MPH and that would only be in the interchanges in larger cities such as houston/minneapolis, new york, atlanta etc all of which are on our list for the next 12-18 months, and that would get me up to 3300 in D(3) and 2500 in OD.  and I know my wind resistance will increase drastically towing over 62MPH (we have owned several campers, driveable and pull behind) but i also know that going 55-60 when traffic flow is 75-90 on a 6 lane interstate with 8 lanes (each direction) during rush hours is just down right dangerous. i had the burban going 83mph just to stay out of the way in Minneapolis to pick up the 454 (yes i had the 6.2L maxed out at 3600, and it still lived to tell the tale)

anyway i would think either one of those cams should get me a nice increase for a flatter tq curve, and a 454 should be able to bring the TQ in pretty low anyway
1988 V10 Suburban 5.7L TBI/TH350 39K on rebuild 4.10AR GM14FF/GM10SF 235/85R16 & 18.4-16.1

1988 V20 Suburban 6.2L-J/TH400 CA truck, 125K G80 14FF/ GM10 4.10AR GVWR 8,600

1977 Ford Granada ~450HP 302 2bbl/C4 27K original 2.47 215/70R14

Offline Rattler12

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Re: Gen V 454 into 88 V20 burb
« Reply #12 on: April 03, 2017, 08:25:10 AM »
IMHO a 110 LSA will give you a lumpy idle and a lumpy idle sounds awesome but just means your gas mileage and torque is suffering at lower rpms.
83 C-10 shorty 454, 5spd, 3:73 posi

Offline MuddiGGEr25

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Re: Gen V 454 into 88 V20 burb
« Reply #13 on: April 03, 2017, 11:35:27 PM »
IMHO a 110 LSA will give you a lumpy idle and a lumpy idle sounds awesome but just means your gas mileage and torque is suffering at lower rpms.

Yeah thats what i have been reading, its "doable" but not recomended with the TBI, but the first link (the 260AH) says it can be used with the stock chip and stock converter..

I am not trying to make a monster out of it, but rather just let it breathe as much as possible with the peanut port heads and standard exhaust. I want to be able to leave it in OD (4L80E is capable) and tow the flat lands. if im hitting a 9% grade then im downshifting anyway.

Speaking of 9% grades, i hit a few of them in wisconsin this weekend while picking up the 454/4L80E and the 6.2L could barely get to 45MPH from a dead stop at the bottom, so i really think the 454 is a good upgrade even if i install it and leave it stock while i look into different cam and intake options, as the 6.2L only made something like 230-240 ft-lbs @2000 and the 454 without a towmaster chip already puts down 385 @ 1600, thats a 60% increase in TQ and i gain OD



Another quick question before work... any recomendations on a 32-35PSI fuel pump? needs to be able to flow 50GPH, not sure if i will have to grab a 50PSI fuel pump and regulate it down to 28--35
1988 V10 Suburban 5.7L TBI/TH350 39K on rebuild 4.10AR GM14FF/GM10SF 235/85R16 & 18.4-16.1

1988 V20 Suburban 6.2L-J/TH400 CA truck, 125K G80 14FF/ GM10 4.10AR GVWR 8,600

1977 Ford Granada ~450HP 302 2bbl/C4 27K original 2.47 215/70R14

Offline big_al273

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Re: Gen V 454 into 88 V20 burb
« Reply #14 on: April 05, 2017, 11:46:08 PM »
find out what the factory fuel pump for the engine was it may be able to be put in a squarebody tbi sending unit, if not there are a few gm pumps that fit that sending unit so you should be able to find an oem pump that will work for you
91 Chevy R3500 Crewcab future project
89 GMC R3500 Cab & Chassis Tool truck project
88 Chevy V30 Crewcab Ex-firetruck
87 Chevy R20 Crewcab future project
84 GMC K1500 winter beater