Just picked up a basketcase 91 T/A with the TPI 305. The previous owner ran it without any oil so the motor is locked up. I won an auction for another 305 TPI with 67k on it on ebay, I'm wondering what I can and can't use. My car has 168k on it so I want to use as much of the 86 engine as I can since it's complete from the oil pan up to the intake. Since the 86 has v-belts and my car has a serpentine setup, I'm guessing I won't be able to use any of the accessories, correct? Both cars are automatic, so the cam should be the same. I know they changed the valve cover bolt pattern in 87, but could I still use the 86 heads with the engine without any problems in my car? Are all of the sensors the same, could I reuse the 86 sensors as well? Just trying to get all potential problems cleared up before I drop the engine and car off at my buddy's place for him to put it in. From what I've read, the only differences between these two engines are the serpentine setup, the different valve cover bolts, and the absence of an air meter before the intake.

 

as long as the serpentine setup is complete there's no reason you couldn't switch it over. I'm pretty sure the cam is different as th 89 would be a roller and the 86 would be a flat tappet. I think as long as you use all of the 91 parts ( intake, sensors,computer) you shouldn't have a problem. I'm not sure but because of the cam you might need to run the 86 knock sensor.

 

The cam doesn't affect the knock sensor. Bore diameter does. Since both are 305's, no issue.

The big issue is that the '86 is a mass air flow (MAF) system and the '91 is speed density (SD). They use completely different sensor and computer systems. Your best bet would be to use the longblock only of the '86 engine, putting your '91 TPI set-up on it. You may run into some valve cover clearance issues, but they will be minor. The '86 is a bit of a downgrade with the flat tappet cam, but with the engine out you'd have the perfect opportunity for a cam upgrade. And, flat tappet cams are a lot less expensive than roller lifter cams.

 

looking for some input, 2 years ago I bought a 87 GTA that was originally a LB9/MM5. The car sat for 15 years, before I got it running again. Someone back in the 90s did some serious mods to it, and I’m looking for some fuel pressure help.

the car was modified in the following
L98 short block
running the original 305 heads (I’m assuming they got bigger valves)
non-adjustable regulator
19lb injectors
SLP tri-y headers and CAI
Smog system gutted and removed
Based on the lope I assume it has an aftermarket cam also LT4 hot cam?
dual cooling fan conversion
Custom tune

since I bought the car I put a ported base plate on and an adjustable regulator.

I never measured the original fuel pressure and I don’t know if the pump is stock or not.

I have the fuel pressure adjusted to 49 psi right now.

My question is is that a good pressure for high compression heads, or should I dial it back to 45 psi.

 

You should start your own post Gravedigger....

GD

 

LOL this may have been my first post on here!

Sadly, that T/A is still sitting. At least it's been kept inside though. Never did get the income I needed to get it going, but it's a priority if/when I ever get a new job that actually pays more than my monthly living costs.

 

The roller motor will be better than the older non-roller. More cam.

I would not spend a lot on a 305. for the same basic money you can drop in a 350.

 

Sitting for 14 years! The parts list will be long and toothy on that one. Took an act of congress to bring my 86 TA back from 11 years sitting in a greenhouse.

GD

 

305's are like spare puppies - at some point we all end up with half a dozen that are perfectly good - we just can't afford to feed and house them and the effort to mold them into something useful is usually too great when you already have adult engines that have been well trained. Those training wheels models just end up under the stairs looking at you with scared beady eyes through the gaps in the boards.

GD

 

Not me. I had three or four of them in various conditions laying around at one point. I threw out a couple that needed rebuilds, gave another away, traded the one that'd run to a buddy for his TBI pickup. Haven't had that problem since. Give em away.

 

Frankly for a basic half ton truck engine - an F body 305 making near 300 torque really would be just fine. People just look down on them - somewhat unreasonably. They are quite serviceable and reliable. Just not glamorous. They are great fun for kids on Christmas morning - I mean you know they are only going to play with it for like a day if even that - then it's back under the stairs again. I always keep one around for emergencies. Because..... reasons.

GD