Ok, I know it has been asked here before, but I am not really finding much info on this. Also being new to corporate motors from traditional Pontiac doesn't help me much. A good friend has a pre 86 350 that has just been rebuilt that I can virtually steal. It is a short block, and I dont have much in the way of money right now, so all I can afford is the short block, and I would for the time being have to use everything else from the 305. I know the 305 heads might raise compression to much, but where this is not my everday driver, if it does, that is ok as I can wait until I can afford heads. Will these 305 heads bolt right up with no problems? Also, will the stock fuel pump be able to supply enough fuel for this? Will the TBI computer be able to adjust to the larger motor? Anything I need to be made aware of? Thanks guys and or gals who may help me out with this.

 

Not sure why this might have been moved, as I am not really asking about TBI specifically. I am asking about swapping a pre 86 motor into an 88 TA that has TBI.

 

I have a 90 vette L-98 bottom end but using LO-3 TBI heads and intake and electronics, my ecm seemed to deal with it fine

 

Your compression will depend on the type of pistons in the 350. If the 350 has the usual dished pistons then swaping on the 305 heads should result in about 9.5 to 1 Make sure you do the math.

As for computer mods. It might run on the 305 chip, but it won't run good. You should get a chip for a 350 and swap to a 350 nock sensor and esc module. You'll also have to swap to 350 injectors.

 

The stock fuel pump being able to feed it will depend on the head and cam choice. The fuel pump would be able to jsut feed a stock 350 at the stock fuel pressure, but anything more will require a new fuel pump. Id suggest looking into getting another set of heads for it. The stock cam could be reused if you just want to get it going, but a set of 083 heads or something similar would be a much better choice. A set of 350 heads with 64 cc chambers should put you around ~9:1 with the run of the mill dished pistons, which would be fine with the stock cam. If its got flat tops your CR will obviously be higher and, this would probably prevent you from running any sort of 305 head.

 

bmmontess

I'm running all stock 89 camaro electronics, and top end on my vette 350 and it runs pretty strong

 

The trucks that I've tuned locally that have made the 305 to 350 swap required quite a bit of retuning to get running right. Most of the engines were on the edge of the BLM routine being able to compensate for the added fuel needs. They ran ok, but not acceptable in my book. Part throttle was pretty good, because the fuel corrections were making up for most of the difference. Because the BLM's were lean, the correction was even applied at WOT, so that wasn't too far off from stock, but stock sucked. What was really noticable was the AE or pump shot tuning. Once I got the VE curves closer and the AE ironed out the motor ran much smoother and gas milage improved. Cold start was also much better. These ecm's have a good bit of self learning built in but all it takes is a bumed O2 or reseting the ecm for the engine to run like dodo.

I guess what's exceptable tune wise varies from person to person. I guess I'm kinda spoiled with being able to tune my FI. Where the average guy that's used to tuning carbs is used to putting up with more.

 

Thanks for the replies. I will go ahead with the swap, and then hit a few yards for the 350 injectors, along with knock sensors. Might also get a fuel pump for a little more peace of mind. Depending on the pistons, I might be able to get away with a thicker head gasket. I haven't asked him what the exact specs on the engine yet, but will do so before I get it. Again thanks. I am an old carb guy, but am willing to learn what it takes to toy with and tune a FI setup. I have access to an old laptop, what exactly would I need to hook this up into my car, along with what program?

 

I don't know how complete your pre '86 short block is but I think you'll need a flexplate, oil pan, and vibration damper. Someone will correct me if I'm wrong.

 

Yeah you must use pre 86 timing cover (good luck tring to see the timing tab) damper oil pan and flex plate or flywheel.

 

Oh I forgot if the dip stick hole on the block is on the driverside by the head, the dip stick will not fit with the camaro firebird exhast manafold.