Engine Block Cracked

[Fbody383]

Survive is relative - yes it will work until it doesn't. Will you need a different bellhousing? I think you'll need a customer transmission mount because I believe the T5 is canted over 20ish degrees.

PS - our experience is that optis are not as bad as they're made out to be... Does Lingenfelter still have these? https://www.lingenfelter.com/product/BAI-LTCC.html I didn't call to see.

[64GunPilot]

Survive is relative - yes it will work until it doesn't. Will you need a different bellhousing? I think you'll need a customer transmission mount because I believe the T5 is canted over 20ish degrees.

PS - our experience is that optis are not as bad as they're made out to be... Does Lingenfelter still have these? https://www.lingenfelter.com/product/BAI-LTCC.html I didn't call to see.

Isn’t the LT1 the same bellhousing bolt pattern and depths as every other SBC? I’ve been running the old 305TPI with T5. From what I read I thought the LT1 bolts right up bellhousing flywheel clutch and all. I may have misunderstood something here. I guess I need to do some more digging. I got Time. I’ll do some more research.

[Supercharged111]

I'm under the impression that the LT1 should bolt in and go unless they're balanced differently in which case you'd be in it for a flywheel. My Opti was installed in 2014 (knock on wood), but it was an AC Delco that they quit making.

[BryanL]

Paging Gary. He ran the T5 behind his LT and should know what's needed along with if it will last.

It will definitely work-but maybe like the Ford's that used to always bring a spare T5 (especially at Hallett).

I'm racing an LT now. I remember a conversation with Mitch about them sorting out the opti issues but don't remember what they did-Glenn probably knows. Do you have the complete pullout with wiring harness?

Nice find OIF - https://www.bailey-eng.com/product/l...der-converter/

[Alien]

Isn’t the LT1 the same bellhousing bolt pattern and depths as every other SBC? I’ve been running the old 305TPI with T5. From what I read I thought the LT1 bolts right up bellhousing flywheel clutch and all. I may have misunderstood something here. I guess I need to do some more digging. I got Time. I’ll do some more research.

Your 305 is a 1pc rear main, correct? I can't remember if all TPI's were the later style.
Yes, the T5 bellhousing bolts right up to the LT1, and the T56 bellhousing will bolt up to the 305.
Canton pan fits both 305 and LT1

I've run my (world class) T5 for a few years behind the 305. I did go through it and did some of the standard upgrades (bearing retainer I think?) quite a few years ago when I dropped in the LT1. A lot will depend how you drive it to make it survive. No sidestepping the clutch on the standing starts, don't just slam your shifts.

I'm using the T5 clutch and hydraulics. I took the flywheel to get balance matched to the LT1 flywheel, just to be sure. Don't remember what they did, but that particular flywheel was on a few previous engines.

5.3L is nice and if something major happens I'll go that route. As mentioned, the longblock is the cheap and easy part. It's all the other stuff that adds up. Exhaust and intake manifolds if you don't have them, custom y-pipe, engine crossmember notched (sometimes), trans crossmember (Holley is great, but interferes with my Alston subframes), accessories, oil pan and Improved trap door for oil control, hoses, wiring...

[64GunPilot]

Your 305 is a 1pc rear main, correct? I can't remember if all TPI's were the later style.
Yes, the T5 bellhousing bolts right up to the LT1, and the T56 bellhousing will bolt up to the 305.
Canton pan fits both 305 and LT1

I've run my (world class) T5 for a few years behind the 305. I did go through it and did some of the standard upgrades (bearing retainer I think?) quite a few years ago when I dropped in the LT1. A lot will depend how you drive it to make it survive. No sidestepping the clutch on the standing starts, don't just slam your shifts.

I'm using the T5 clutch and hydraulics. I took the flywheel to get balance matched to the LT1 flywheel, just to be sure. Don't remember what they did, but that particular flywheel was on a few previous engines.

5.3L is nice and if something major happens I'll go that route. As mentioned, the longblock is the cheap and easy part. It's all the other stuff that adds up. Exhaust and intake manifolds if you don't have them, custom y-pipe, engine crossmember notched (sometimes), trans crossmember (Holley is great, but interferes with my Alston subframes), accessories, oil pan and Improved trap door for oil control, hoses, wiring...

Gary, thank you for the confirmation. Everything I’ve read says it’ll work. Nice to have a fellow racer onboard with the idea. I’m $4000 into the 5.3 build. I probably should just finish it out. Just need another $1500 worth of crap, and then I might be ready for the Dyno. Time, effort, and money. Striving for reliability. Can’t make up my mind.

[BryanL]

What about running the T56 from the LT? You don't need 6th gear but I assume if 6th is broke there are other issues. People will still pay some strong money for a core I hear if you sold it to finish the LS.

LT was second at Hallett. My car sat for over 10 years and has three race weekends under it without an issue of the LT-I'm not going to blame the fire on the LT's plastic fuel lines.

For everything discussed I think the most unreliable part would be the T5. The T56 you can't hardly break at our power and tire.

Do you have or can you use your existing exhaust with the LT? Just looking at all the small stuff that goes into either and where you want to put your energy.

[Mojave]

What about running the T56 from the LT? You don't need 6th gear but I assume if 6th is broke there are other issues. People will still pay some strong money for a core I hear if you sold it to finish the LS.

LT was second at Hallett. My car sat for over 10 years and has three race weekends under it without an issue of the LT-I'm not going to blame the fire on the LT's plastic fuel lines.

For everything discussed I think the most unreliable part would be the T5. The T56 you can't hardly break at our power and tire.

Do you have or can you use your existing exhaust with the LT? Just looking at all the small stuff that goes into either and where you want to put your energy.

What do you mean don't need 6th gear? Per the 2022 rules:

6.27.3 All gears including reverse must be functional and able to be used to drive the car

[Gerno]

He’s just saying none of us 6th gear, it’s a waste to have but yes you I cannot remove the gear per the rules . Hell, I never even use 5th

[64GunPilot]

What about running the T56 from the LT? You don't need 6th gear but I assume if 6th is broke there are other issues. People will still pay some strong money for a core I hear if you sold it to finish the LS.

LT was second at Hallett. My car sat for over 10 years and has three race weekends under it without an issue of the LT-I'm not going to blame the fire on the LT's plastic fuel lines.

For everything discussed I think the most unreliable part would be the T5. The T56 you can't hardly break at our power and tire.

Do you have or can you use your existing exhaust with the LT? Just looking at all the small stuff that goes into either and where you want to put your energy.

Bryan,

I have been youtubing T56 rebuilds. Seems like it is within my capability. I need to learn this stuff, and a good excuse to buy some more tools like the depth gauges ect. Could always bring the T5 as a backup trans. The current 305TPI is running the aftermarket headers that the rules allow. I'll have to use the factory LT Headers, and your right, I might be able to bolt the current exhaust piping right up to the headers or at least minor adjustments made. Maybe another headache averted.

The good news is I get to make up my mind very shortly.