Allright, in a bind, friends GTA is knocking, we've pulled the valve covers and verified the knock in the lower block.
Problem is now this, I have the following things sitting around and need to know the easiest way to get a motor in this car. The is an '89 GTA automatic.

1 1985 4 bolt block
1 1988 4 bolt block (truck block)
1 1989 2 bolt stock block (still in car)
1 2 pc. 383 crank (new)
3 sets standard, unmachined 350 rods
1 set 350 rods clearanced for 383 application
2 sets stock perimeter bolt heads
1 set stock centerbolt heads
1 set centerbolt TFS TW Heads (G2 I think)

I have a few stock sticks lying around and all the block need to go to the shop first. I'd like to use the '89 block to retain the roller lifters, but I don't know the extent of the damage. Also, it would be much easier to let the car sit 'till spring while I built the motor indoors where it is nice and warm. I'll most likely use cast pistons as the car is mostly a daily driver and a mild cam. Beginning with these parts, what would y'all do? Also if using the '85 block what problems (if any) would we have mating it to the '89 tranny? Thanks guys.

 

I'm going to assume for the moment that the blocks are 350, and the heads are 350 TPI.

Use the 88 block, a set of stock rods, a stock crank, and one of the sets of stock perimeter bolt heads. This will exactly duplicate what he has now. Put a better cam than a stock one in it. This way you get to build a motor before tearing the car down.

If the perimeter-bolt heads are not stock 350 TPI, then the decision matrix becomes a bit more complicated.

The "best" motor would probably be the 85 block, the 3.75" crank, the rods to match, and the TF heads. But then of course you'd need to use a flat-tappet cam, probably some other valve covers, maybe not the existing intake, etc. But of course that combo should be good for easily 75 HP more than the stock 350.

If you have the heads from the truck motor, throw them in the garbage, do not attempt anything resembling performance out of them.

Use hypereutectic pistons. Far better piece, still under $10 a hole. http://store.summitracing.com/partdetail.asp?part=8449

 

Yep, all 350 stuff.

The '89 has centerbolt heads, it is a TPI.

I don't mind using the flat tappet cam, the motor will be mild, and there are a few nice grinds that will work with the stock ECU.

I was thinking along the libnes of what you mentioned with the '85 block with the 383 stuff on it and the TFS heads. I have valve covers for them, already modified to fit. The engine has alot of the same stuff on it as mine, big mouth manifold AS&M runners for the intake, so it won't really matter which type of head I have. If I go that route however, will I run unto trouble with the tranny mating the block, I've never had to use pre '85 blocks in post '85 cars, so I don't know if anything changed. (BTW anyone know a good starter to use in the 383 set up if we go that way?) Thanks!

 

Sorry, forgot the last line, I'm thinking of going with the cast because thay are not as brittle. Should there be detonation I don't know how some of the cheaper hypers do in those situations, and I've seen casts take one helluva beating. In regard to this, y'all can feel free to educate me, but I don't see the bonus in a mild motor for the hypers as opposed to the casts.

 

The hypers fit the bore tighter, and the material they are made of is a better heat "insulator", so the heat of combustion stays in the chamber and does useful work, instead of heating up the oil. I know of no problems with their "brittleness" unless the engine is operated so as to produce detonation, in which case there's a greater chance of them breaking; but that shouldn't be an issue with a reasonable CR, and FI.

There are no issues with the trans. Everything there will bolt up, as long as your flex plate is correct for the block's rear main seal design.

I have a CVR min-starter that I got for the 400 that used to be in the car (and will be going back soon!!), works great, I highly recommend it.

And I'm sorry, I screwed up, I meant center-bolt not perimiter-bolt both times I said it. I was actually referring to the ones you have that aren't on the motor: if they're TPI heads, not truck garbage, then you could almost entirely assemble the new motor without touching the old one, until it was actually time for the install.