I want to swap out the slow 85 305tpi and put in the zz4 crate engine ,or maybe a cheaper crate engine(depends on budget). What all do I need to change? I want to keep the tpi setup.

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85 305tpi Trans am
flowmaster exaust
K&N air filter, 4:11 rear gears

 

The Big Mouth intake will fit. Bear in mind it is an Edelbrock casting that TPIS ports. If you are willing to port it yourself you can save money. You'll need bigger injectors - the 305 has 19# injectors and the stock 350 has 22#. Better runners and an upgraded chip will be required to take advantage of all this. You'll want to port match everything if you're so inclined. Porting the ZZ4 (L98 vette) heads will make a big improvement too. There's also exhaust - with all this you'll at least want a 3" cat-back. Headers will make a big difference with all this increased air-flow.

You may want to reevaluate the ZZ-3 cam that comes in the ZZ-4 motor. Then you'll want tranny, suspension and brake upgrades, alum driveshaft, strut-tower brace, upgraded ignition...it never ends, dude...

 

It fits fine. See my pics here:
http://24.1.139.249/images/112400/
Its the stock 87-92 piece that has different bolt angles.

I went the time in my sig and made 280 HP and 380 TQ at the rear wheels with the ZZ4 cam. Its a decent piece.

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1991 Camaro Z28
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