LTx vs. LSx in z32

[rsicard]

hawaiifiveo: My wife has a 1994 FULL SIZE Buick Roadmaster with a LT-1 350 engine, 4L60E transmission and a Non-Posi rear end. There are VERY few cars that can match this Buick at the starting line including a 5.3 pickup. It accelerates like MAD. Just hard to imagine it being upgraded to a 383!!!

[hawaiifiveoh]

I know they are torque monsters, no doubt about it, but I'm trying to really do what's gonna get the best results, I've had plenty of "stupids" with my dsm's, and am not looking to jump into anything. Anything is a possibility, I'm just tying to decide exactly what I want.

[hawaiifiveoh]

And as far as pricing, I'm gonna only going to be comparing motors, not tranny's yet.

[Slammed68]

For the price difference of a 5.3 and a 6.0, you would be shooting yourself in the foot with a HUGE gun right now to "save" money with the 5.3. Just think about pricing of cam and heads... I know this price difference vs power difference was DEFINITELY worth it to me.

 

I have a buddy that has been running a STOCK (ARP rod bolts only) LQ4 with a turbo setup on it in a foxbody, and he just laid down 630rwhp, and has been driving it daily for over a year. There isn't one thing wrong with a rod bolted LQ4 until you are making serious power. He cranked it to 13 psi to race a busa the other day and the motor still purrs like a kittin after 10+ races with the dude.

 

LQ4 will be your best power per price motor, unless you can find an LQ9 for cheap. Dont waste your hustle with a 5.3, no reason to unless a $400 difference isn't worth some major power to you.

 

LT1's are tree fiddy chebby motors, and yes, they are, from my personal and multiple freinds experiences, hard to get power out of. Friend with a 70 trim setup on his laid down 446rwhp and 511tq, IMO, look at the difference from that and 630rwhp on the SAME turbo on an LQ4 and that right there would be my eye opener on power potential.

[hawaiifiveoh]

Wow...that's pretty nuts, won't lie. I keep looking around, and yea, for the little bit of extra money, the lq's seem to dominate. Thanks for the help man, I'm pretty sure on the decision to go 6.0, it's all just saving up and finding my stuff now.

[hawaiifiveoh]

Just a quick ? about the older z's...something like Slammed68's, is there any firewall modification involved? And if not, I'd assume the swap would be quite a bit easier... I was at first thinking z32, but hell, if I find a decent chassis to work with for cheap, then I'd be open to something like that. I've never really been around those cars, and they are growing on me.

[tonys99ramair]

Hawiifiveo: I would seriously look at a LT-1 or LT-4 and get is for cheap money. Then find a T56 to join up with it. Rebuild the LT-1 or LT-4 to a stroker 383 cu in for about 6.3 Liters. Use SCAT crank, rods and SRP Pro Pistons. Then purchase AFR-195 heads for it and a good intake manifold, bigger fuel injectors, harness and computer. This should cost less than a good 6.0 liter LS engine and yield MORE HP and Torque.

 

That sounds like spending a lot of money to make power! I had a 6.0L, cam and headers and the stock heads milled .030 and the car made 442/413 to the back tires. LS based motors respond so much better to mods than LT motors do, trust me I have had both. I see intake to oil pan with PCM and harness 6.0's for $1000-$1500 all the time. To me it is a no brainer in the choice of LT vs. LS motors.--Tony

[hawaiifiveoh]

So far my plan is 6.0, cam + supporting valvetrain, full exhaust, intake, and 5.3 heads to bump the compression, or stock heads milled, whichever I find makes more power. Probably go with a TH400 trans for now with a manumatic shifter, if I like it, keep it, if not, save up for a t56.

[tonys99ramair]

So far my plan is 6.0, cam + supporting valvetrain, full exhaust, intake, and 5.3 heads to bump the compression, or stock heads milled, whichever I find makes more power. Probably go with a TH400 trans for now with a manumatic shifter, if I like it, keep it, if not, save up for a t56.

 

Milling the stock heads will be cheaper, and yield the same if not more. I do believe to 6.0 heads flow more than a 5.3 head. Good thing about going with a 6.0 motor is the ability to run GM's L92 heads, those are some bad boys there! Cheaper than damn near any aftermarket head and will out flow damn near all of them.--Tony

[Slammed68]

All you have to do to the 5.3 heads is get the intake side valve opened up to a 2.00, so the 317's valves will fit right in, like i did. In the end it should flow like a 317, but have 11:1 compression, and you dont have to pester with getting custom sized pushrods. The smaller intake valve was the only setback to the 5.3 heads, and with this done, problem solved. Why do you think Texas-Speed sells 5.3 heads instead of 6.0 heads

[tonys99ramair]

Why do you think Texas-Speed sells 5.3 heads instead of 6.0 heads

 

Because the guys that are buying the TSP head kits are usually buying them for a 5.7 LS1, not a 6.0 LQ4/9. You don't see/hear of to many people swapping 6.0 heads for 5.3 heads . And as far as custom sized pushrods go, with any sort of a big lift cam (like these motors love) you are going to have to get smaller push rods anyways.--Tony

[Slammed68]

lol, why spend all that money, milling, custom pushrods, this and that, when you can have better flow, and 11:1 compression on an LQ4, just by buying the 5.3 heads and getting the intake valves machined to fit the 6.0 heads valves, and drop them right on..

 

Just sayin, I spent 260 bucks on heads, and still have the 317's for whenever I boost my ♥♥♥♥. I swapped my 6.0 heads for my 5.3 heads and WOW.. just got it tuned last sunday and it is AMAZING the power difference just 260 bucks made. Went from no traction issues in 3rd at 55, to being able to smack the go pedal and delete the traction almost anywhere in 3rd gear...