Lt1 engine swap questions

[Moofus02]

Found a f body lt1 motor. It broke a rod at the big end. Didn't hurt the motor. They replaced it with a corvette motor. Block heads cam pistons all good. Comes with the y body accessory drive. I know the lt1 has light weight pistons but are the rods the same as vortec l31 rods?

If I put this in a gmt400 and do a coil on plug conversion what computer should I run it with, 0411/p59?

 

[Erik the Awful]

The stock LT1 pistons are around 532g. That's not lightweight in my book.

From what I've read, the Vortec rods are excellent. If you're asking if you can drop a single Vortec rod in place of the broken LT1 rod, I wouldn't. I'd either find a single LT1 rod and verify it's the same weight as your current rods, or I'd get a full set of Vortec rods.

Your main problem is that they're all press-fit and will require special tools to disassemble and reassemble. I'm sure somebody can jump on here and say they did it in their garage, but I won't use a shop press to remove a piston pin and then trust that the piston is just fine. I did try installing new pistons onto old rods in my garage once, and after an hour of it not working, I took them to the machine shop.

What's your goal with this truck? Since you're making the swap to coil-on-plug, I'll assume you're wanting performance, but it sounds like you're keeping the stock cam and heads.

 

[Supercharged111]

95+ LT1 got the powdered metal connecting rods. I believe 350 accessories bolt right up.

 

[Moofus02]

The stock LT1 pistons are around 532g. That's not lightweight in my book.

From what I've read, the Vortec rods are excellent. If you're asking if you can drop a single Vortec rod in place of the broken LT1 rod, I wouldn't. I'd either find a single LT1 rod and verify it's the same weight as your current rods, or I'd get a full set of Vortec rods.

Your main problem is that they're all press-fit and will require special tools to disassemble and reassemble. I'm sure somebody can jump on here and say they did it in their garage, but I won't use a shop press to remove a piston pin and then trust that the piston is just fine. I did try installing new pistons onto old rods in my garage once, and after an hour of it not working, I took them to the machine shop.

What's your goal with this truck? Since you're making the swap to coil-on-plug, I'll assume you're wanting performance, but it sounds like you're keeping the stock cam and heads.

Aluminum head lt1 out of a firebird comes with corvette accessory drive. I was going to use the pistons in a truck motor and 383 this block and swap into a 99 suburban. It's cheep enough and complete just broke lol
And yes cam headers tune etc

 

[Schurkey]

LT1 would have flat-top pistons w/ 4 valve reliefs. Truck engines--TBI and Vortec--use dish pistons.

That engine have Opti-Spark?

 

[Moofus02]

LT1 would have flat-top pistons w/ 4 valve reliefs. Truck engines--TBI and Vortec--use dish pistons.

That engine have Opti-Spark?

Yes optispark. Going to look at it tomorrow. Want to make sure the heads are OK when rod let go

 

[Supercharged111]

Stick a 96-97 OBDII reluctor, balancer hub, and timing cover on there. Then you can run a 411 with no cam sensor. The opti then only exists as a distributor.

 

[Moofus02]

Went and looked at it today. Block isn't hurt no ridge and good bores. Piston kissed the head and bent an exhaust valve but looks like head and piston are OK. Out of 96 bird he put 94 corvette motor in it and swapped stuff over. Comes with corvette front accessories, exhaust manifolds and 2 complete intakes for$250. All the bolts and valve train stuff is there. One correct rod and I could put it back together

 

[Schurkey]

I'd be on that PRONTO.

Not sure I'd re-use that piston...but even so, sounds like a winner. I paid that for a Vortec short-block.

 

[Supercharged111]

Corvette LT1s got 4 bolt mains fwiw.