jtroiano

I'm new and have been reading a lot, just to much info to make a decision.

I have bought a 6cyl 74 firebird and going to put a 73 nose on it. I want to put in a newer chevy engine. I want 700hp, thinking T56 Viper 6 speed. I was thinking turbo. I want 25mpg when cruising.

I think the MPG can be accomplished.

What donor truck/car should I be looking at? I may even graft in the gauges and stuff. 5.3 or 6.0 liter?? Money is a slight concern.

It doesnt have to have a turbo to start but before I install the engine I would like to upgrade it so that its ready. Cam? valve springs? ARP bolts? Do I have to upgrade the rods and pistons?

VTEC? Cylinder drop off for mileage?


A little about me. Can MIG,TIG fab anything. Been working on cars for 30 years. Been into the Diesel seen for a while. Lost touch with the car performance side. I have my own auto repair business.

I'm open to ideas.

Thanks
Jon

ls1 1990 VN

If i was in your shoes with a auto repair business & worked on cars for that long, i would be looking at something more unique for your 74.
You are looking at the Viper box! stick trhe V10 infront of it.

01ssreda4

iTrader: (96)

A turbo 5.3 would do nicely

jtroiano

You ever listen to a V10? They sound like sh*t! Plus the 25 MPG would be out the window.

I think with a turbo I could get close to the goals with a 5.3 liter.

What years would be the best and what upgrades would I need to consider.

Thanks for the replies.

Jon T

ls1 1990 VN

You want 700hp and are concerned with MPG!!!!
Some people don't deserve a performance car.

Russell PTA

^ lol

ItzFox69

so you want good gas mileage and high horse power, think less turbo more bottle. thats what i would do anyway. Do a stroker with some good heads intake and internals and you could almost be at the 600 end just on motor. but thats big bucks. ive got a buddy with a carbed 383 and just on motor he's crankin about 578-585hp to the wheels. He puts the squeeze on it and the car just effin screams.

trans_am7935

iTrader: (15)

go with a small motor (5.3, 5.7) and throw a twin turbo step setup on it. you might be able to wing that. the key to good gas mileage is all about efficiency, and it is in the heads. get the best small port, high velocity heads you can find (AFR 205/210) and get them massaged by Tony. that should get you there.

jtroiano

I have an 8000 pound truck that has over 1,000 ft pounds of torque at the back wheels and get over 20mpg. (j-sautorepair.com second page)

Doesnt the new Corvette get like 30mpg cruising?

I know if I use the power it will not get good mileage. But just cuising on the hwy with the right gearing it should be very easy to do. If I dont put the big spoiler on the back and maybe no hood scoop. Also I think the Trans Am fenders with the vents would help with air flow from under the hood. Keep it light. I was wondering if the cylinder cancellation could be programmed to work when it wasnt under boost.

trans_am7935, Why two turbos? Maybe one with the exhaust wrapped to keep the heat in??

Jon T