I have acquired a 1988 Firebird Formula. It has a 305 TBI / 5 Speed with a rod thru the pan.

What wouyld be the current horsepower of this combination? A VIN search shows the motor to be:

305ci V8 LB9 (1987-1992)

Would I benefit by replacing the 305 shortblock with a 350 shortblock, and leaving the rest alone.

Should I replace the heads, and which ones would be bolt-on. I have a set of 441 heads but they would not have the right intake bolt pattern. How about VORTECs? Or whatever. Or would the 305 heads with their small cc vloume be best anyway?

Should I make any inexpensive or labor only mods for a little extra power as long as I have it torn down.

The VIN does not show trans or rear end specs either. Curious as to what they likely are as well.

Any suggestions/help would be appreciated, especiallt reference to URLs that would cover the subject of this port.

 

I would also appreciate any cam / chip suggestions. I LOVE performance but will be making this a daily driver that I will AutoCross with SCCA occaisionally. Since it is a Formula the suspension should be more than adequate.

 

first you can get alot more info from your rpo code sheet.. its either on the console lid or the trunk compartment lid..

heres the decoder https://www.thirdgen.org/cgi-bin/rpo/index

the easiest to do would be just get a 350 block and put your 305 tpi stuff back on it..

 

The tags mentioned are no where on the car.

But I would like to know if anyone can answer the original questions I asked.

 

https://www.thirdgen.org/newdesign/tech/techdb.shtml

Looks like it was 220 hp originally.

You can do what you suggest. Assuming the busted rod didn't damage the cam, you could use it in a roller 350 block ('87-later) as well. You should probably get dished pistons in the 350 to keep the compression down (305 heads have 58cc chambers, whereas 350s have 64cc). It would also be a good idea to put 1.94" intake valves into the 305 heads and do some basic porting work to allow the 350 to breathe a little.

Assuming the rod took out the cam, and/or you don't get a roller 350 block, a flat-tappet, computer-compatible cam can be had for not too much cash. Be sure to use flat-tappet length pushrods if you go that route (roller lifter pushrods are shorter).

Porting the plenum would be a good idea while you're at it, too. And an adjustable fuel pressure regulator. Most recommend using a 350 knock sensor and module for this swap. The factory used 22 lb injectors in 350s vs. 19 lb for 305s, but running higher fuel pressure can compensate for that with the smaller injectors.

 

If you really are only changing the block/pistons, i dont think you would see much gain in horsepower (+10 maybe?) but since you are going up 45ci, you would probably see a pretty nice gain in low end grunt. I could be wrong though, because i am not 100% sure on what you are swapping over (didn't have time to read all replies)