I have a 92 rs with a stock 305 in it and i recently bought a stock 454 HI PERF from a guy out of a 87? dually silverado and had a couple questions i was hoping some of you could answer...


- Can i use the stock 700r4 trans? will it bolt up? ive done some research on it some say it will bolt up and hold, some say it will bolt up but would get shredded, and some say it wont even bolt up... if i dont use the 700r4 i could just buy a 400 turbo and put a shift kit in it

-Do you think i would be safe with a stock 10 bolt rearend? with stock gears?

- what distributor set up would be the best for this?

-any full length headers that will bolt up with no problems?


if you could answer any of these questions for me it would be greatly appreciated! i am young and dont wanna make a mistake with the bad combinations of parts...

 

it`ll bolt up, won`t last long..the trans or the rear but you could fix that as you progress, headers are not easy, it`s either hooker or ed quay or lemons for true bolt ups and even those are "true" bolt in.

 

thank you very much idk if i wanna just find a cheap 400 turbo trans and clean it put it back together then swap the trans and the engine at once... then just leave the 10 bolt in it for now

 

Don't be taken in by the "hi perf" cast in the block. All factory BBC engines are considered Hi Perf because they were always compared to the SBC.

You can yank any distributor from a SBC and drop it into the BBC. The simplest way is to just drop in a large cap HEI unless you want a computer to control the distributor.

Any transmission swap other than a third gen 700R4 will require some modifications to swap it in. The crossmember mount will be in a different position and you need some way to attach the torque arm. The easiest way to do the swap is to buy an aftermarket torque arm with a crossmember designed for the transmission you want to use.

The factory 7.5" 10 bolt can be beefed up a bit but nothing you do to it will make the tiny ring and pinion any stronger. The diffs have been broken on the street and have survived on the dragstrip. You're rolling the dice on how long it will last if it's abused.

Typically, like most cars, if you build a high performance engine, the entire driveline needs to be upgraded to handle all the extra power.

 

thank you very much for the help guys

 

Yeah your 454 will bolt up. The trans will hold under moderate use with stock (NON STICKY) street tires. However WOT shifts will tear the clutches up pretty quick, especially 3-4. If you wanna run a TH-700R4 I recommend getting a built one.

I put a TH-400 in mine. You will need an aftermarket torque arm and transmission crossmember. I got mine from BMR fabrication (TA002H $229,TCC019 $254) You will also need a new driveshaft.

The stock rear and gears will hold under moderate use with street tires. No high stall converters, no neutral drops, etc. You will probably cut the life of the axle in half though. I had a 500 horse 383 in front of a stock th-700R4/10 bolt 2.73 axle. I left it one legged with stock cooper cobra tires and put a shift kit in the trans. The trans lasted one year of pretty aggressive street driving before the 2-3/3-4 clutches gave up the ghost.

My Large cap HEI fit with no issues whatsoever. However I have heard of people with BBC thirdgens having distributor clearance issues. Any small cap distributor should fit.

Exhaust is the most challenging part of this endeavor. I don't know of any swap headers/exhaust manifolds that fit without issue. I used Dorman exhaust manifolds (674-159,674-161). I had to pound the passengerside firewall in about 1-2 inches to make clearance for the downpipe.

Hope this info helps.

 

yes thank you i will look into those item

 

I too am planning out a 454 swap (well, a 496). I decided I am going to beef up the rear first before doing anything to the engine. Then I will probably do the trans next (2004R most likely). With the trans, I will probably sturdy up the chassis (aftermarket k, sfc, etc etc). Then comes the part I've been waiting for

 

Thats a good approach. I'm biding my time with the TH-400. I'm eventually gonna swap to a built TH-200R4 for the even gear spacing and taller overdrive gear. Its more suited to a big block than the TH-700R4 with its granny gear and 1-2 spacing. Maybe 3.55 or 3.73 gears in the rear. Probably gonna upgrade to a moser or strange bolt in ford 9 inch axle before changing gears.

You should check out BMR fabrication. Their stuff is alot cheaper than Spohn and I'm very satisfied with my crossmember/ torque arm.

 

you think i could keep the 10 bolt if i just beef it up a little?

 

What are your goals.
Roll king? Go for it.
Track star? Get something better.

 

depends like said previously. i want to do a 496 though then eventually supercharge it, so i want drop in the good stuff instead of temporary improvements.

 

Are Silverado, Suburban & motorhome 454s all the same in terms of bolting up? I have access to a running 454 from a 70s Suburban

 

yes it will bolt up to the engine

 

Yes. all big blocks have the exact same motor mount and bellhousing pattern as small blocks. the only difference is that heavy trucks like 450's and cement trucks have tall deck 427s and 366s. There never was a tall deck 454.

 

? do i have to move the motor mounts on subframe forward ??

 

No. The distance from the rear of the block to the mounts is the same for small blocks and big blocks, the extra length of the big block is added forward of the mounts.

 

This is correct. a big block chevy will bolt up to anything that had a sb or LT1. The engine is longer in the front and taller. So you more room between the engine and radiator and more hood clearance. If it had a small block the big block will drop right in.

Now you will need to make room for the exhaust, and if you run the stock low profile intake you should not need a cowl hood.