496 vs. 467 BBC- opinions???

[tiger9297]

Have a '90 K5. Doing a BBC swap. Have a complete TBI 454. Needs rebuild. I have a set amount of money I'm willing to spend. I'm not going to go over. I'm going to change pistons, cam, headers, etc. so it will be a stout engine either way. What would you do:

1) build a MPFI 467- according to Dyon2000 should be right at 525lb/ft. TQ

2) buy stroker crank and build 496 but use stock TBI and intake. Maybe down the road spend the money to buy the MPFI unit? According to Dyno2000 this engine should run 550 lb/ft TQ.

Strangely enough both engines will produce almost exactly 390 peak HP.

 

[nvrenuf]

Search for posts by "RUSS", he built a tbi 496 for his 90 crew cab and was having problems. You can try to pm him but I don't know if he still comes around.

 

[tiger9297]

I just skimmed through a number of his posts. His truck had a stock TBI 350 that he swapped for a TBI 454 much the same as I am doing. However, he still used the stock chip and the stock fuel pump. That's why he was running lean. According to the people I have talked to as I've planned this build the fuel pump for the 350 simply won't cut it. Additionally, the computer will have to have a new chip. I may be proven very wrong but I think I have those areas figured out. I'm just wanting to get opinions on the MPFI 467 or a TBI 496.

 

[DEMON44]

MPFI is definately superior to TBI..........but more CI is always better too.


I'd get the cubes now and feed it better later. Mines going to 496 when my parts arrive.

 

[blazinzuk]

MPFI just because its way better than TBI, what ever you build I would put the MPFI on it

 

[tiger9297]

Nothing like getting two exact oppostite contradicting opinions one right after the other.

 

[HarryH3]

Shawn's Potent Rodent had an MPFI 496 lurking under the hood at one time. That thing was scary fast!

Go for the longer stroke, it not only adds more cubic inches, it also provides a longer lever for the pistons to work against. Makes a real torque monster. I was VERY happy when I stroked out a 350 to make it into a 383. I can only imagine the smile that would be on my face the first time I put the hammer down on a 496.

 

[Russ]

I changed both fuel pumps out to high pressure pumps and had a chip burned twice for this engine, but still have not been able to get it to run right. I keep my scanner hooked up to it everyday when I drive it and am constantly fine-tuning the fuel pressure and tps to try and get it to idle, while not running too lean at speed, but am not having much luck. I am sure that if I had the smarts to burn my own chip I could probably get it to run pretty good over time, but I don't really care to even try and learn to do that.

If I had it to do over again, I would definitely go with one of the MPFI units. They are bound to make more horsepower and run better than my TBI unit. I am running the bored out 454 TBI and an edelbrock TBI manifold that I port matched to a set of Edelbrock aluminum heads. From my personal experience, I don't believe the TBI will ever be able to give this engine the fuel it needs to run well.

Russ

 

[tiger9297]

Thanks Russ,

Thats what I needed to hear. I am leaning towards the MPFI 467. Howell will burn the chip and hopefully everything will work right when it all comes together. I don't think the displacement difference between a 467 and a 496 will make all that much difference. I figure 25 lb/ft. of TQ and NO difference in peak HP. When you are talking 500+ peak TQ 25 lb/ft is not that much to sacrifice for a good running, reliable engine. Thanks for all the input.