73-87chevytrucks.com
73-87 Chevy _ GMC Trucks => Engine/Drivetrain => Topic started by: 78 Chevyrado on May 10, 2010, 01:18:45 pm
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Its about that time, cams wearing out and oil psi is getting low, plus I suddenly have a lot more money coming in. ;D I have to buy tires for the car and wheels for the truck (2 weeks), and then everythings going into the engine!
I'm gonna stick with the stock 350 short-block, but add summit heads and a comp cams roller cam as well as an offy dual port intake manifold. I been wondering about that intake, so I'm going to try it. If it sucks I'll get a performer EPS.
I'll be getting my short-block rebuilt, and with the summit heads it'll make right around 9:1 comp ratio.
I'm getting Summit heads SUM-152123
http://www.summitracing.com/parts/SUM-152123/ (http://www.summitracing.com/parts/SUM-152123/)
New Distributor - I'll be buying a bunch of stuff from this guy if all goes well
http://cgi.ebay.com/ebaymotors/SBC-BBC-CHEVY-CLEAR-CAP-65K-HEI-DISTRIBUTOR-6500-CL-_W0QQcmdZViewItemQQhashZitem51923cab44QQitemZ350345800516QQptZMotorsQ5fCarQ5fTruckQ5fPartsQ5fAccessories (http://cgi.ebay.com/ebaymotors/SBC-BBC-CHEVY-CLEAR-CAP-65K-HEI-DISTRIBUTOR-6500-CL-_W0QQcmdZViewItemQQhashZitem51923cab44QQitemZ350345800516QQptZMotorsQ5fCarQ5fTruckQ5fPartsQ5fAccessories)
Offenhauser Intake 6007DP
Engine Rebuild Kit (should give 8.9-9.0 comp ratio with the summit heads) Actual part number may change depending on which exact bearings I end up needing, but these are the pistons i want.
http://www.summitracing.com/parts/FEM-MHP133-311/?rtype=10 (http://www.summitracing.com/parts/FEM-MHP133-311/?rtype=10)
Comp Cams Roller Camshaft Kit for an XR264HR
http://www.compcams.com/Cam_Specs/CamDetails.aspx?csid=157&sb=2 (http://www.compcams.com/Cam_Specs/CamDetails.aspx?csid=157&sb=2)
Comp Cam Roller Tip Rocker Arms 1412-16
http://www.summitracing.com/parts/CCA-1412-16/?rtype=10 (http://www.summitracing.com/parts/CCA-1412-16/?rtype=10)
I'll be keeping the edelbrock 1406, since it only has like 10k miles on it
At some point soon it'll have electric fans.
And once I get it all buttoned up, I'm getting 2.5 dual exhaust with cherry bomb vortex mufflers. I'll get 2.5 since I have half of it already.
Once the engines built, I'm having a 700r4 built and will adapt it into my chassis. I'll be keeping the 3.73 rear gears.
Thats all thats concrete at this time. the engine will be painted something like coke can red, since my interior is red.
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Oops. Wrong section. Could one of the admins move this to the members projects section? Thanks fellas!
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the cam bearings in the engine kit are babbit. Is there any special kind of cam bearings I should get to go with a roller cam? Type and/or brand would be appreciated.
Also what are the best main/rod bearings. The ones in the kit say tri-metal. Should I get tri-metal cam bearings?
No racing, but I fully intend to keep my foot in it as much as I please.... I'm not light footed till money's tight ;D
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Cam shouldn't take any different bearings, how old are they? I would replace them with the same manufacturer bearings.
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clevite is a good bearing brand.
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Why a dished piston? I'd runa flat top with those heads. Is your engine a roller block?
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Nothing but envy here ;D
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Cam shouldn't take any different bearings, how old are they? I would replace them with the same manufacturer bearings.
The engine kit I want to get comes with tri-metal bearings for the rods/mains but the cam bearing in the kit are babbit. I've seen tri-metal cam bearings. If enough stuff in the kit isn't what I want, I'll buy it all separate so I don't have a bunch of left over stuff.
Why a dished piston? I'd runa flat top with those heads. Is your engine a roller block?
Those pistons aren't in stone until the machine shop says they'll work right. Depends on how much they deck the block and what head gasket I use.
I figured the dished piston to get around 8.9:1 or 9:1CR. I don't want to have to run premium fuel in it. Whats the highest CR I could run 87 or 89 octane in? Obviously I want the highest CR I can get but not run 91 octane.
No, the engine isn't a roller block. I'm getting the retrofit cam and lifter kit with the links between the lifters.
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Vile is right, with that size of combustion chamber you will be fine with flat tops. That's what I have with my 72cc Dart heads and I can run 89 octane fuel if I wish. You can always bump the timing back a little too if you are having an issue with octane. Also, are you buying the Offy dual-port or do you already have it? Word is that is one of the absolute worst intake manifold designs ever for making power. Or one of the greatest for limiting power, depending on your point of view lol If you are curious to try it and don't mind buying a Performer afterwards then by all means try it out but I haven't seen one good thing said about it.
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Vile is right, with that size of combustion chamber you will be fine with flat tops. That's what I have with my 72cc Dart heads and I can run 89 octane fuel if I wish. You can always bump the timing back a little too if you are having an issue with octane. Also, are you buying the Offy dual-port or do you already have it? Word is that is one of the absolute worst intake manifold designs ever for making power. Or one of the greatest for limiting power, depending on your point of view lol If you are curious to try it and don't mind buying a Performer afterwards then by all means try it out but I haven't seen one good thing said about it.
Flat tops might make their way in there. I won't know for sure until the machine shop says, but I'm all for it if its better for me.
I don't have the offy yet, but both me and my dad want to see one. Kind of a novelty... :P I've heard a bunch of bad about em, but I also heard about 1/3 good things. I'm gonna try it and see what happens, though I'll never know how it did until I try another manifold. I don't know, I keep going back and forth because it does cost twice what an edelbrock eps does, so we'll know when I've bought and paid for something.
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I think I may go with these heads
RHS Cast Iron Vortec The summit ad says they have ductile valve guides, but RHS's site says they're bronze.
http://www.summitracing.com/parts/RHS-12410-01/ (http://www.summitracing.com/parts/RHS-12410-01/)
It will get an edelbrock 2716 EPS vortec intake.
Still sticking with the XR264HR Roller Cam
I want my comp ration between 9:1 - 9.5:1 somewhere in there is fine.
The truck will have headers and 2.5 dual exhaust, and h or x pipe. cherry bomb vortex mufflers.
Anybody have any bad things to say about the RHS heads? I don't hear of them a lot, but I've only come across good things.
Anybody ever heard this cam? Comp XR264HR Roller.
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The 12407's have iron guides and 1.94/1.50 valves. The 12410's have bronze guides and 2.02/1.60 valves.
These guys (http://www.flatlanderracing.com/) offer those head assemblies for $415 each.
The XE256 flat tappet cam has the same LCA and duration @ 0.050", so my guess is it will sound something like this:
http://www.youtube.com/watch?v=_l27PwABKLQ
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The 12407's have iron guides and 1.94/1.50 valves. The 12410's have bronze guides and 2.02/1.60 valves.
These guys (http://www.flatlanderracing.com/) offer those head assemblies for $415 each.
The XE256 flat tappet cam has the same LCA and duration @ 0.050", so my guess is it will sound something like this:
http://www.youtube.com/watch?v=_l27PwABKLQ
Sweet links! That truck sounded good, now im really itchin to get mine done.... ha and i haven't even taken it apart!
I noticed on that site you put up they have 2 versions of that head. One for a flat tappet, and one for a roller cam. Does this reference an OE roller block and self aligning rocker arms? and if so I should use the flat tappet head since I'm getting a RETRO fit roller cam? That's what I ASSume it all means. plus the roller cam head costs a bit more, but otherwise all the specs are identical.
And I also notice those heads accept the old Pre-86 intake bolt pattern and they also accept vortec intakes. Does it really matter which version I use? because I can get a performer EPS in either version. I kinda figure since they're vortec heads, might as well get the vortec intake.
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Oh, I forgot. You will likely need the 12410-02 heads with the heavier springs. There is a chance that because your cam selection is so mild the lighter springs will work, but I doubt it. Double-check with Comp as RHS is a sister company and thus they use Comp springs, so they should know. The two different assemblies are simply for flat tappet versus hyd roller (rollers usually need significantly more spring pressure to keep the valves under control). It has nothing to do with the block or lifters used.
Based on what I've read, DO NOT assume you can use an early intake. Yes it will physically bolt on, but the ports will not be even close to matching and there is usually not enough material to grind the intake to a port match. That bolt pattern was offered for racers using raised port single plane intakes, which can be made to match. USE A VORTEC INTAKE.
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WARNING - non-expert advice alert! Just the ramblings of a madman.
Some more thoughts on the issue: When I say I doubt that you can get by with 12410-01, what I mean is I doubt that is the recommended or preferred choice. But actually if it were me, I might try it for the following reasons.
1) The cam you've chosen is mild. If you go with 1.5:1 rockers and keep the rpm well under 5500 (peak hp will likely be around 5000), I bet the valves will stay under control.
2) Yes the springs are lighter in pressure, but they are also lighter in weight (single spring vs double spring). Apples-to-apples a lighter weight spring is always better. Of course, this isn't an apples-to-apples situation but that is still one point to the credit of the single springs.
3) Even the single springs are pretty stout. 124 lbs. on the seat with 308 lbs/in rate. That's pretty good. Factory GM roller cams have run with much less than that. Of course they are even milder than your selected cam.
But one major strike against such a gamble is if you do float the valves, you will dramatically shorten the life of the springs, lifters, and cam. Roller cams/lifters do not last long after valve float that was severe enough to leave even small surface imperfections on the lobes.
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Makes perfect sense. Thanks!
So I'll get a vortec intake and the roller cam heads. I have been wanting a bit bigger cam, and after listening to that video, I'm pondering moving up to the next step, XR270HR. I'd love that one, because it has a nice idle. Plus the power in comps dyno charts isnt too different from the XR264. I'd like my powerband up between 2000-4000, because off-idle max power is pretty useless since I never floor it from a standstill with a load. Where I need power the most is on the freeway at 70mph for passing, etc. Even when I get my 700r4, I'll still be towing in 3rd gear if it's heavy so at 70, I'll be turning around 3000rpms no matter what tranny. Plus I'd really like to get a bit of idle to it, I've been jonesing for that for like 6 years since I sold my mustang, and it had a big rumpity rump cam.
This is the XR270HR cam in a camaro 358.
http://www.youtube.com/watch?v=ZFSXNYRL6as (http://www.youtube.com/watch?v=ZFSXNYRL6as)
I'm actually fairly happy with my trucks power like it is, except for now and then, so basically any cam i get will be a huge improvement over stock. So if I lose a little bit of torque in the new engine to have that sexy idle, I'm for it.
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The XE270HR should be a better choice. It'll still be very streetable with a good idle, but have better midrange/top-end power. If I were choosing between the two, I'd go with the 270 cam hands down, especially if you'll have 9:1 or better compression.
Please keep us posted. I am officially very interested in this build. Do you think you might have it dyno'd?
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The XE270HR should be a better choice. It'll still be very streetable with a good idle, but have better midrange/top-end power. If I were choosing between the two, I'd go with the 270 cam hands down, especially if you'll have 9:1 or better compression.
Please keep us posted. I am officially very interested in this build. Do you think you might have it dyno'd?
The 270 is the cam I want, but I chose the 264 because I didn't want to go too big. I've never messed with a roller cam before, so the specs I know for flat tappets apparently are useless. i think the equivalent flat tappet to the xr270 roller is an xe262, and the flat tappet 262 sounds real lopey at idle even in a 383. so ill be learning as I go.
I want to have it dynoed, if I can find a place to do it. I'd love to final tune it on one. if there are places around here they're well hidden. I'm going to call year one and see if they do it, since they have a hot rod shop on premises.
Here's the rebuild kit I picked to go with the 64cc RHS heads...
http://www.summitracing.com/parts/FEM-MHP133-311/ (http://www.summitracing.com/parts/FEM-MHP133-311/)
says it should end up approx 9.6 or 9.7 to 1 comp ratio with 64cc heads. Pistons are Dish, with two valve reliefs 12cc. The exact part number may change depending on what undersize bearings I end up with.
I got to looking at how much more a fill up of premium would cost over 87 octane and its only $12 per 40 gallons, so I can swing that.
Also thinking (depending on piston to valve clearance) I might go with 1.6 rockers instead of the 1.52 since the RHS heads have a max lift of .600 I am getting new rockers. Haven't decided between full rollers or just roller tip.
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First baby step today, I ordered a new distributor. I'm on the way! ;D
http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&item=350345800516&viewitem=&_trkparms=algo%3DLVI%26its%3DI%26otn%3D2&category=33690 (http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&item=350345800516&viewitem=&_trkparms=algo%3DLVI%26its%3DI%26otn%3D2&category=33690)
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Let me know how you like the new distributor, I want to convert my engine back to HEI.
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Let me know how you like the new distributor, I want to convert my engine back to HEI.
I'm not gonna be using it for a while, but just looking at it it sure does look nice! Seems to be HIGH quality, and well put together. It's complete from one end to the other including the intake gasket. Can't beat that with a stick. ;D
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Sweet, so looks like all I will need is a new power and tach wire.
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i been figuring up machine shop costs, and upgrading my crank and or rods a little, and for about the same price, I can get this shortblock, all assembled ready to go. also it should give me a 9.1:1 comp ratio, so basically its everything I wanted for my shortblock. What do you guys think of this one? anybody have any problems out of them? anything to watch out for?
its GM 12556121 short block
http://paceperformance.com/index.asp?PageAction=VIEWPROD&ProdID=184534 (http://paceperformance.com/index.asp?PageAction=VIEWPROD&ProdID=184534)
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That distributor bothers me. It sure seems like an awful lot of talking to sell a distributor for half of what a lower priced new one costs anywhere else. It's been my experience over the years that anyone who talks that much about a deal that's already unbelievable is full of it. Sounds to me like they can't even give em away.
Have you considered checking Northern Auto Parts for your rebuild kit? They will put together any combination of parts you want and have great prices. You can also upgrade several parts on their kits such as bearings, timing chains, gaskets, pistons, rings and cams to name a few. Just my 2 cents worth. Good luck.
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I wouldn't have a problem using a GM Performance Parts small block, but there are plenty of people out there saying they are junk because they are made in Mexico. I've got a similar decision in my future and will definitely consider this route. It is attractive when you consider the cost of machine work and assembly to recondition one. I see a new GM short block as less of a risk than a rebuilt one for the same or less money. I have no actual experience with them, though.
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i been figuring up machine shop costs, and upgrading my crank and or rods a little, and for about the same price, I can get this shortblock, all assembled ready to go. also it should give me a 9.1:1 comp ratio, so basically its everything I wanted for my shortblock. What do you guys think of this one? anybody have any problems out of them? anything to watch out for?
its GM 12556121 short block
http://paceperformance.com/index.asp?PageAction=VIEWPROD&ProdID=184534 (http://paceperformance.com/index.asp?PageAction=VIEWPROD&ProdID=184534)
If I were building an engine, I'd use a short block that was either prep'd and assembled by a performance/race engine shop or prep'd by a top notch machine shop and assembled by me. That GM short block will be reliable, but it represents a performance compromise for convenience sake. For example, the pistons and 0.025" deck height will compromise quench and compression, which costs some power and efficiency. The turning friction of that shortblock will undoubtedly be higher than a professionally prep'd assembly. So on and so on.
If your goal is minimizing hassle and you don't mind leaving some performance on the table, then OK. But there are probably much better deals out there on assembled short blocks. Keep in mind, there is actually some merit in using a rebuilt block over a "green" block.
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If you don't go the shortblock route, why not just find a decent late 80's block that has provisions for a roller cam? That's what I did and I had my guy reuse my World heads with shorter pushrods and a GM HT383 roller cam in it. The pistons are GM performance parts with a 9:1 CR. It runs great on 87 octane and if I'm careful I can get 15mpg repeatedly--and this is in a 79 K10.
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All the machine work and certain parts I want cost about the same as the shortblock, and I know nothing about the few machine shops around here, so I'm gonna try to go with the gm short block. There's enough of them around with reviews to have a good idea what ill be getting. I know a few people who used it and they couldnt be happier. and itll save me some trouble and its convinent. I spent more on the paintjob than its prolly worth, cuz i had them do all kinds of little things that dont really matter, but i liked em. I'm gonna spend more on this engine than I should, i know it now, but Im in it for the enjoyment. see how my combo comes out and all that. plus i want it to turn at least 5500RPM. I dont need it to really, but nothing sounds like a smallblock wound out over 4500. there's just a lot that goes into a shortblock that has to go together properly and im not sure enough of myself to properly build it the first time, and i dunno if i can take the machinists word on what parts i need. Im bad at trusting mechanic type people because every single time i do, i get screwed over. The last one tried to tell me i needed a new bumper on my focus when it was really an engine mount... haha.
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Did you notice that that GM short block does not have a provision for a mechanical fuel pump? So with that short block you will have to run an electric fuel pump. This one should work if you are looking to keep the mechanical fuel pump.
http://paceperformance.com/index.asp?PageAction=VIEWPROD&ProdID=183227
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Did you notice that that GM short block does not have a provision for a mechanical fuel pump? So with that short block you will have to run an electric fuel pump. This one should work if you are looking to keep the mechanical fuel pump.
http://paceperformance.com/index.asp?PageAction=VIEWPROD&ProdID=183227
Yeah i saw that. Thanks! I was going to get the 2 piece seal block so i could keep the mech pump, but i really want that one piece seal, enough to get an electric pump. Once i get everything together, this ones gonna take a while to get running. so much to do.