BBC Help...

[88_50]

Hello everyone,
 Im new to the Site and new to BBC, but not new to engine building...or asking questions. I know that the correct combination is key to an efficient running engine, so thats why I decided to post on here to get your opinions. So here's what I currently have...

1990 Chevy C3500 ECLW 2WD with a 454ci, TH400, and a dually rear. The 454 block is a 4 bolt main 14015445. The heads are 14092360 peanut ports. And of course TBI and computer controlled distributor. Supposely this engine has just had a fresh rebuild.

I bought this truck for my son, while I was overseas. Unfortunately I wasnt around to test drive it. I found it on the internet so my wife and son test drove it and brought it home. After coming home for R&R, Ive come to realize I probably bought a dud. My problem with this truck is it feels like a dog. I dont expect it to run like my F350 or my 383 racecar, but I do expect it to have some ballz. While I was home I pulled the pan off to make sure the bottom end looked ok. The bearings all looked fine, so I didnt worry about the rings. I did replace the plastic sleeve for the oil pump drive with a Summit one piece. I then replaced the timing chain for a double roller. I also thru on a set of Hedman Headers, true dual exhaust with Flowmasters, MSD wires, new plugs, cap and rotor, and an Edelbrock TBI intake. Guess what...no change. Still runs like a 305. Throttle response seemed to be a little better, but still has a lot of bog off the line. So I told my son as I was heading back to Afghanistan to just drive the truck until I got back. Then we would tinker with it some more. The day after I leave he tells me that he over-heated the truck and now the oil is milky. Apparently he wasnt watching the gauges and somehow thru the serpentine belt. An expensive lesson to say the least. Now Im scratching my head wondering with which way to go. Do I replace the peanut heads with another fresh set and call it done...or do I have some fun with it? It gets 7 mpg now, so I couldnt hurt that aspect. The other option would be to throw out all the computer stuff and install some 049/781 heads, small cam, Edelbrock intake, small Holley carb, HEI, and a mech fuel pump.

Im not sure if going away from the computer will harm anything. The cam shouldnt cause any issues with the brakes cause it doesnt have a power booster. The trans is a TH400, so the comp doesnt control it either. The only issue I can think of is the fuel system. Its TBI now, so I guess I could get an electric fuel pump that has a return on it and plumb into the existing lines. Not sure.

Not sure what to do at this moment. I know there are plenty of people out there making good power with the pp heads. Is there a pp head casting that you recommend? Or go with the 049/781 heads? If I go with these heads, do I need to change the pistons? Any suggest on a cam for either heads?


Any help would be greatly appreciated.

[bake74]

     I am not the best to comment on your post, just wanted to say that others will be for sure, you just have to be patient.  Just wanted to welcome you from California, and thank you for your service.

[motion427]

Yes,those TBI 454 are pretty much a dog at the factory compare to a built 383 for sure.
If you really want more power,I'd have to say,remove the TBI unit and go with a carburetor setup.
Then you can go with a better head and cam setup.
Those TBI unit ussually run on the lean side at the factory,with some mods,it's only gonna get worse.

It can be done by making good power with a TBI unit,but a lot of work and alot more money,need a lot of patience too.......

Their was a link that I posted a few weeks ago here on the site,a magazine article about a cheap 454 that made 440+hP with lots of torque with a penut port 454,RPM intake,750 Holley,with a Comp Extreme energy cam.That would be a pretty good setup for a big dually.

What tranny,gear ratio,and tire size that this bad boy has ?

[88_50]

Bake74, thanks for the welcome


Motion427,
 The trans is a TH400. The tires are 16's. And I have no clue what gears are in it. My guess is a low gear. The rpms are a bit high on the highway. Wish the truck had a tach in it. I would give you the rpm to speed info. Im just going by my calibrated ears...haha.


Yeah, its a nice truck. I tried to post a pic of it, but says I cant cause its 534kb

[VileZambonie]

Use photobucket

it doesnt have a power booster

Do you mean it doesn't have a vacuum booster? It should have hydroboost unless someone made it manual brakes which would be pretty stupid.

Did you change the oil after you replaced the intake? Where did you set the timing? To be honest you went about this all wrong.

Dropping the oil pan and timing chain etc while not a bad thing was probably a waste of time and money. Changing the intake without changing the cam and eliminating those valve rotators was another waste of time and money. At this point I would find out why it overheated/threw the belt and if any engine damage occured. If you have to pull the engine you should be able to build plenty of power and keep the TBI setup. If you determine the engine is OK and you just have some risidual oil/water mix from when you opened it up we can walk you through the process of figuring out why it's a slug.

[88_50]

Yeah it has a hydroboost...sorry, I forgot the name.

I did change the oil when I did the intake because I did the oil pump driveshaft and timing chain at the same time. The main reason for me to pull the oil pan was to see if it really was rebuilt. Like I said, it runs more like a 305. As for the timing, a friend had borrowed my timing gun and I couldnt seem to reach him while I was home. So before I tore it all apart, I brought it up to TDC and marked where the distributor and rotor were both sitting. I know its a bit redneck, but the best I could do without the gun. The truck fired up immediate, so I know its back to where it was before I started. I had told my son to run it by a shop while I was gone to have the timing and rockers checked. But he overheated it before he could take it there. Now Im hoping it just hurt the heads at the worst. Im praying it didnt get hot enough to stick the rings.

My son says when he started the truck up for me to check the oil for water, he noticed that one of the pulleys seemed bent. Im still waiting to hear back from him which one it is. I just wish he would have listened to me always preaching about watching his gauges....ahhhh 16 year olds...Im sure his mind was more on his g/f sitting next to him and not his truck.

My main goal when I started on this project was to make sure the 454 was honestly rebuilt, add the Edelbrock TBI intake and headers for a little more power, and add some chrome to make it look better. Little did I know this would turn so ugly.

VileZambonie, what combo do you recommend for the TBI setup? At this point, Im wondering if I would get better power and gas mileage out of a 750cfm carb and dual plane intake. My ears are open. I definitely respect your knowledge on the matter and appreciate all your help.

[88_50]

Here it is...

[Layne]

That's not a 1990....

[motion427]

Yes,like VileZambonie wrote.
Would have to figure out what caused the overheating and hope theirs minimum damage,and go from there.

Didn't Edelbrock had a top end package(heads,cam,intake) for those TBI 454's ?

Truck looks nice by the way.

[VileZambonie]

That's not a 1990....

Why not?

Definitely get rid of those heads. Look on this page for some recommendations.

http://www.tbichips.com/454ss.htm

[Layne]

I thought the 3500's didn't change over till 92. Could you order the nbs?

[VileZambonie]

In 1987 The C/K series was done in the old body style and became R/V. In 1988 The C/K's were that body style.

[Layne]

I see. I'm going to step out of this gracefully lol.

[topp]

In 1987 The C/K series was done in the old body style and became R/V. In 1988 The C/K's were that body style.

Only the 1500 series.  HD changed over in 92 to the new body style:
Here is a 1991 3500: http://rides.sporttruck.com/ride/1015433/chevyboy4/1991/chevrolet/k3500/index.html

[royo]

The bb that i have likes alot of timing. When i bought it . it was a dog all i did was give it a little more advance and it turned into a screamer.Ive got a 5000 rpm chip in the 6al. It will blow the tires off it