iroc_you

Just got a killer deal on a 454 with 33k miles and am thinking about putting it in my 86 iroc,so i am here for all the info anyone can provide me,any tips or tricks to make installing it easier.I am needing info on manifolds or headers what works and what dont,the easiest way to do away with the tpi comp and wires and what i need to swap to carb,any info and help will be greatly appreciated and when i get it done there will be tons of sb stuff for sale.

t-top havoc

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booboosean

THE DEVASTATOR

There's another someone did. I don't recall the user name, he used stock Chevy 3800 exhaust manifolds. Search chevy3800, IIRC.
( edit )
Subframe connectors should be in your plans if you do go Bigblock.

86mailman

Im in the prosess of doing the same thing to my 86. Your biggest issue will be your headers. I used the patriot (h8012) from jegs. They are $200 and with minor modifications they slip right in. if your car came with a 305 or 350 your big block will fit right in using the factory motor mounts. You will need to remove the distributor to make a little easer going in.

1gary

Whoa.Slow down there BB man.If your 54 is one of the truck blocks,those heads don't flow well at all. Ya might want to check that out. It's a hell of alot easier with the engine out of the car than in it.

AlkyIROC

Depends a lot on exactly which generation of 454 he has. Since he got a deal on a low mileage engine, I'd assume it's not a Mark IV engine unless it's a rebuild.

The older Mark IV's have lots of potential and even the truck heads with oval ports can be modified to make a lot of power. There are hundreds of BBC head casting and very few are considered "bad" castings like the SBC choices. The most popular oval port castings are 781 and 049 and they were mainly found on trucks. For a street engine running under 5000 rpm, I'd stay away from the 990 rectangular port castings.

If it's a Gen V block, then it's pretty much a boat anchor. It has some potential but has too many limitations to make it a desirable swap. The peanut port heads and non adjustable valve train are junk.

A Mark VI engine gets into the Vortec era. Not as desirable as the Mark IV but still has a lot of aftermarket support.

Swapping a SBC for a BBC is pretty straight forward. The distance from the transmission bellhousing to the motor mounts is the same. Since the block is longer with greater bore spacing, the front of the block sits forward from where a SBC sits. This means some modifications may be required for room between the block and the rad for water pump, fan etc.

As mentioned above, headers are the most complicated part of the swap. No factory manifolds will fit properly. The Hooker swap headers will work but they're expensive and not a 100% perfect swap. Those Patriot headers are a cheaper alternative but still require some modifications to get them to work. A BBC header should have at least 1-7/8" primary tubes. If it has 1-3/4" tubes, it will choke the engine from making any real power defeating the purpose of swapping in the BBC.

t-top havoc

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https://www.thirdgen.org/forums/engi...ot-my-big.html


Sorry about the 3800-- thats COMPLETELY WRONG!!..

It was 2003 truck, 8100 series!!

As Alky stated, post some info on what year // generation the block is. Lots more can be passed on to you.

diablizzard

iTrader: (8)

there is a set of headers for sale right now

https://www.thirdgen.org/forums/engi...uper-comp.html

86mailman

a gen v block with a good set of aluminum heads should make a good bit of power, right?

86mailman

I have the gen v block. but my plan for stage 2 of my build is to trash the stock drive train, and replace with good stuff. Then stage 3 will be body work and paint.