1979 Firebird needs new engine, question

[HarleyMo]

1979 Firebird, base model, was a stock 301 that doesnt run and not really insterested in rebuilding it. Want to drop in something larger for street use. Somewhere between 350-400 hp. Question: Pontiac 350 or 400 or something else. Not sure if the big block 400 will drop into the base model firebird that year. Suspension ? motor mounts? Tranny? (it has a turbo 350), rearend ?

I know, sorry for all the newbie questions, but Im finally getting around to trying to get this car running, Ive had it sitting in my various garages for about 10 years now.

Thanks

Harley

 

[melsg5]

you could do a pontiac 455 but not sure if the trani and rear will take that amount of torque, pontiac engines do not have small and big blocks they are the same block with different cranks or cylinder width.

 

[Goatman]

all V/8 Pontiac engines should mount the same transmissions, mounts,but the exhaust for the 301 is different from the 350,400,455 engines so they would have to be changed also, but rearends are sufficent to hold all but the highest HP apps

 

[HarleyMo]

Thanks guys, yes, I had expected that I would have to replace headers, exhaust and accessories (alt, power steering etc). Since the 350, 400, 455 will bolt right in, is that true for all years of those engines or just the ones from late 70s. I read there was a change between late 60s early 70s and the later engines. Wonder if there were any years I need to steer clear of.

Thanks again

Harley

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[HarleyMo]

Has anyone dealt with S & S rebuilt engines ? www.rebuiltautoengines.com

They have rebuilt 400 long blocks for 1,500 plus core and then a 455 stroker that the guys says "Basically it is the same as a 400 with the exeption of the 455 crank, balanced rotating assembly, 455 standard bore pistons, and a Ram air 2 cam" for 2,700 plus core.

Wondering how much HP I could get out of these with a good intake, carb, ignition and headers.

Thanks for all the input for a newbie guys.

Harley

 

[melsg5]

if you go with it get the Ram Air III cam

 

[bar]

Here's a few tips I picked up from Pete McCarthy out of High Performance Pontiac magazine. He's built Pontiac engines for decades.
1. Don't use a factory Pontiac cam. The aftermarket grinds are much better. Pick a cam with a tight lobe spread like 110 degrees or less, and it will build much more power. The factory cams were like 114 degrees. The duration will depend on your rear end gearing. If you have a high gear like 308, go with a mild duration like 224 or less.
2. Don't worry about high compression heads. You'll do better with 9:1 or less on pump gas. If you used the high comp heads, you'd have to run your ignition timing back, which would kill your power. Pete found that the mid 70's Trans Am heads built more power because they had a smaller exhaust valve. One of the markings for such a head is 5c, but I'm not sure about the others.
Good luck, and have fun!