ok i just pulled the 305 out of my car because i get a 350 for it. my buddy has a 89 GMC jimmy with the 350 TBI system. but the other day he blew a head gasket and now he has a cracked block. what i'm thining about doing to selling him my L69 305 HO motor that was in my firebird and sell it to him for his truck but what i need to know is will the computer run right with the L69 heads (414 i think is the casting)

the 305 has been bored .030 over, 350 crank installed , ported and polised L69 HO heads. if installed in the truck it will have the edlbrock TBI intake and it will have all the emissions hooked back up to it. but i'm thinking that the motor will run rich becuase the computer is for a 350.... can i just swap out the PROM in the ECU and put in a TBI 305 PROM in the ECU and call it a day?

i'm don't know much about FI .... i'm running a carb on my 91 firebird LoL

 

The PROMS are not interchangable. You are going to need to brun a new chip with any new motor that is not stock with these cars.

 

You need a 305 chip out of a 305 tbi truck. I would also get 305 injectors off the same truck you get the chip from or just use your injectors on his truck. How well does the engine run in your car with the carb?

Steve

 

it ran real nice till it has a bad lifter. then today i ripped apart the botton end of the motor and found out that the main bearings where shot and when the bearing went it took the crank with it so i'm doing a full rebuilt on the motor i'm going to take the motor in and get it honed out. thats the only thing wrong with the block.

as for the injetors. i think i will be fine with the 350 ones becuase the heads have been ported and plished along with the cam and it being bored over it sould be ok with the bigger one. if it still runs rich i'm just going to put a adjustable fule pressure reg. on the TBI unit.

i will be getting a PROM out of a 305 TBI motor just have to hit the junk yards.

(PS the 305 ran a 15.1 in the 1/4 with the motor out of tune. )

 

One last question. Why did you put a 350crank in the 305 block? I know the stroke is the same but the counter weights are heavier due to heavier pistons in a 350. I would think this would throw everything out of balance, might even cause premature bearing wear.

Steve