Thanks fro adding me to this site, I;m learning as much as i can on turbos in order to create my own Firebird Trans AM GTA. currently running a 305 that id like to twin turbo similar to the banks turbos from back in the day. any info you can share with me in my diy attempt, i have marginal mechanic skills and decent tools.

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First, Love the car. I Love a GTA.
Second, maybe consider a 350?
Third, set out a goal for the car. "Turbo'd" is kind of a goal, but not really. Do you want a 100% street car? Do you want a drag car? How "fast" do you want to spend?

 

Thanks Disney Lincoln, im interested in a street toy thats functional and well built. or well sorted. like the 1980 and 1989 birds with turbos, i know there is a low opinion of the 301/pontiac and skepticism about the old 3.8.. but ended up being an awesome car. A piece of automotive history. So thats kinda where im shifting my focus. its a go between on the 301 and 3.8 i believe. im going to fabricate what i can and trial and error. i figure about 450 hp and 400 tq in a third gen, would make this car an "experience" so with that anyone who has turbo'd a car here would help me sort it out

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A gen 2 3.8 is a good choice to turbo. You can’t go wrong with an LS or 350 though either. I’d skip the 301. Hitting your target hp shouldn’t be a problem with the above engines I mentioned..

 

im thinking 305, first of all, it was free, original 305 car.. may be cool. i blew up a 305 the other day, so i have a 358 on the stand in the event.

 

What fuel management program are you planning to use? EFI? CARB?

 

id like to go e85/methanol injection on a twin setup.. so i like the etomic efi/fitech system, or a carb blow thru set up

 

what would you suggest?

 

Holley Sniper EFI if you plan to use the carb style platform.

 

Keep hood clearance in mind. NOt sure if a blow thru carb setup will fit under the stock hood.

 

I don't want to stiffle your enthusiasm, but really, I wouldn't turbo the 305. It's hardly worth it when a 350 is a free or close to free upgrade. Just my $0.02

 

I personally don't have an issue with the 305 if you're comparing a stock smog era 305 to a 350. The basic build will be the same, there isn't enough tq/hp difference to really mess with entry level turbo selection, and either will meet his modest goals. If building an engine, then I agree with Disney, but with that said, I personally wouldn't bother building a gen 1 these days unless looking for a period correct engine. The gen 1 will just cost you more to make the same hp as an ls.

 

A 4.8 LS makes more hp than a stock 350 of that era. That would be my choice .The benefits far outweighs the little extra money.

 

5.3 makes more and is MUCH easier to get. 4.8s are almost as hard to get as a 6.0.


I am all for him getting his feet wet with the 305. But if you build/buy everything for a SBC and then end up with a LS, its just spending 2x the money to end up in the same place.

You really need to decide for sure where you are going to end up with this project and make a plan and stick to it.

 

911turbo you're right, a turbo ls would be the goal, but there are so many combos. turbo ls would be ideal. Im using the 305 for a test mule as i prep the car and put it together. at least it wont sit.

 

Man, you touched on an important aspect right there. It's better to go ahead and start working on it now than to get caught in the never ending loop of "planning" the perfect combo.

 

305 is another motor that has a huge stigma. As far as the rotating assy the piston diameter is the only thing that is different between a 305 and a 350. So they are both nothing special. Yeh the 305 bore limits valve size. But dont give the 350 heads of that era any credit. Both are far better than a stock GN head and they force feed the death out of those frankenstein chunks of iron.

I built and tuned and .030 over sbe, rv cam ,turd 305 back in the day. Went mid 11s on 150 shot in a 3800 lbs car.

I say, throw a s366 borg on and have fun.

 

yeah buddy, thats NEVER EVER worked for me, when it sits its the pits.

 

I am buddy, just might throw on two hair dryers!!

 

If an LS is your goal you could stockpile your engine and turbo parts while you drive your car as it is now and save the money . Keep your eye on the prize.