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Big block guys

bigblock454 said:
Any details on this? I'm currently planning my 1991 454 TBI build.
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Sure, it was a 70s stock peanut port 454 Marshall engine rebuild that was $500 and came with a truck. I put in a 204/214 cam, weiand street warrior (for peanut ports) stock qjet and headers with 2.5 duals. I tuned it on the chassis dyno and then drove it like I stole it. Though the power is much lower than people think they need this engine hauled my 5500lb k30 on 37s with ease.

That intake will work with your tbi but doesn't keep the egr which I would try and keep.
 
If I remember right the ss454 guys claim the tbi performer is basically the same as the newer alum intake used on the late 454 tbi. I would be tempted to run the stock intake, add the cam and exhaust and a heated o2.
 
80' 427 said:
My 10.50 et avg big block got 9-12 mpg turning 3850-4200 on drag week.

My 8.1 gets 11.5

Edelbrocks belong in the trash

You guys with your desktop quoted numbers are funny.

What do you want this engine to do? My garbage peanut port 454 with no compression, a cam intake and headers made 360hp at 3950 and 500 ftlbs at 2200. Trucks don't need power at 6500 they need grunt. Cams that need big converters are going the wrong way in a truck.

On a side note if you want better mpg out of these trucks slow down. It is easy to see by looking at the "road load" equation you will see all that the higher rolling resistance of big tires and the increased drag coefficient caused by a lift will both increase the the hp required to push a truck though the air at speed.

If it was me I would work to get compression, which will require a dome because of the 118-120 cc most of the big block heads have (not the 76cc listed previously). Then I would have the best set of heads I could afford rebuild. Those 781s will be fine and the big valves won't hurt mpg. Heads that flow air while remaining high velocity will need less cam to make the power you want. Then I would buy a Weiand Street warrior and buy zimmers qjet. The cam will depend on the desired usage and the header primary diameter is going to make a noticeable difference as long as you don't have a 2.25 or something else too huge. I would do a min 2.5" exhaust and consider 3".
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It's merrily a top to get ya in the ball park......:thumb:
 
80' 427 said:
What do you want this engine to do?
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I want the engine to pretty much do anything that I want to do with it, Whether it's using it as a DD, taking it out on trail rides, playing in some mud, or driving to and from whatever trail I go to. I'd like to get better gas mileage than I do with the current 350, but if I'm getting the same with twice the power, I can handle it. Also, when my 350 gets up to operating temp and has been running for about 45 minutes it feels like a gutless turd. So I'm hoping to take care of that also.

I've already bought the speed pro 22cc dome pistons and the 11-676-4 compcam, just waiting on shipping on both. Once I build the short block I'll get the head work done and start looking at intakes and a fuel system. I may take Zim's qjet off his hands, or I may just spring for a fuel injection setup. I've been eye balling the FITech setups and have been looking for all the info I can find on them right now.
 
Buddy of mine just got the FiTech setup for his 521 bbf....... Waiting on cam & other odds & ends to come. I'll let ya know how he likes it.
 
My friend who runs a shop says the only aftermarket tbi efi that hasn't been down hp from a properly sized carb is the MSD atomic. Even the new fast was 40 hp short on a 500 hp 468.
 
I got the FAST EZ EFI first version....I definitely don't think it outperforms that JET carb that I had on it, but I don't think it under performs either. The Jet carb actually cold idled better than the FAST does, but I think its because I might still be a little lean on the idle setting @ 12:1
 
They had a 600 hp Pontiac that was like 60 whp short after the swap. Went to throttle body and individual injectors hp came right back. I am just telling what I know.
 
I just got the speedpro pistons this morning, so I guess I need to check/file the ring end gap. I didn't get instructions with them, but I found this on the internet.
http://www.aa1car.com/library/ring_info_speedpro.pdf

According to that, my top rings need to be 0.017 and my second rings need to be 0.021. Does that sound about right? And this is still a standard bore of 4.250
 
Also, do I need to weigh all the rod ends and pistons and shave weight so they all weigh exactly the same, or is that a race engine type thing?
 
I didn't plan on it. Don't externally balance engines use weighted flexplates and harmonic balancers? I haven't looked much into how to balance a rotating assembly.
 
85 Jimmy said:
I didn't plan on it. Don't externally balance engines use weighted flexplates and harmonic balancers? I haven't looked much into how to balance a rotating assembly.
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Depending on the weight difference of the old pistons to the new ones it'll raise the NVH of your engine.....
 
I just weighed everyone one of the new pistons with their wrist pins and they weigh 31.4 oz. I also cleaned up one of the old pistons that I already removed the rings from and weighed it with its wrist pin, it weighed 31.5 oz.
 
I've always given ring gaps of .004 to .0045 for each inch of bore.
A little more if you want a power adder in the future like nitrous.
 
Pro balancing is a good idea as well as magna fluxing rotating assy
 
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