mhslax6

I see that people constantly mess up LT1 builds so I thought I'd ask the people who know them for some info.

Selling the Vortech supercharger and am going to do a LE2 package with Lloyd's 227/235 .565/.579 110 LSA cam. I'm going to keep the SLP 2OTL for now and change the SLP shorties for LT's. Walls have scratches that I can feel with a finger nail on 3 of the 8.

Want to spend $5K max (including the LT's and Lloyd's LE2 package). Advice??

hrcslam

Stock bore? Stock rotating assembly?

If so, I'd start with getting the block to the Machine shop and bore as little as needed to get rid of the imperfections on the sleeves and have the machine shop inspect the crank and anything else you'll be keeping. Then build a parts list from there.

What are your goals for this build?
Street and strip?
Emissions friendly?
Horsepower target?
What did Lloyd recommend to shoot for for optimal compression ratio?

Boring the block will increase CID and therefore SCR too. The hardest thing for us LT1 guys to do is keep the quench tight and the SCR low with our small combustion chambers, especially after head work (milling them true and flat). Fortunately, our lovely LT1's can run some pretty high compression without the issues most other engines deal with.

I put $4500 into my build, including machine work, heads, cam, exhaust, fuel pump, injectors, tuning program, cables, fluids, sensors, rings, bearings, everything. I think if you do all the work you can, yourself, $5K is a very reasonable budget.

mhslax6

I assume that I'll have to go .30 over due to the scratches.

mhslax6

I'd like to do forged pistons, the stock ones look pretty bad.

hrcslam

Definitely forged pistons and rods. Keep the crank if it inspects good.

Balance the rotating assembly too. What SCR are you shooting for with that cam? Also do you need to pass emissions?

mhslax6

In AZ and its a '96 so I don't think I need to get sniffed, only Obd test.

hrcslam

You are correct. They only pull codes on OBD2 cars. They don't pop hood either if you're OBD2 cause they assume you'll get a code otherwise. I know a good machine shop off Prince Rd here in Tucson, he took a while to do the work, but the work was top notch and the price was right.

mhslax6

Lloyd and my dad talked about the cam/heads but I dont think they discussed the CR yet. I have a Racetronics pump already. Who did your machine work? I'm in Gilbert.

hrcslam

P.O Machine here in Tucson. Cool guy, and he knows his LT1's. It's a little ways drive for you though. Maybe 1.5 hrs or so. The shop is about 45-50 minutes south of Casa Grande for reference.

If I were using that cam, I'd shoot for 11-11.5:1 SCR. I'd use forged flat top pistons, 0.030" over, LE2 heads, forged connection rods, true the block and heads, and run an Impala gasket. Or you could zero deck the block and use a .045" head gasket. I'm running 11.8:1 with a cam slightly bigger than yours -damn near the same really- and I'm zero decked with .043" compressed head gasket thickness, no knocking issues.

Use some NSA rockers with 7/16" studs and hardened pushrods (many stock LT1 come with them from the factory, mine ended up being the right length so I am using mine).

Don't use a HV oil pump, they are not needed on LT1's and do more harm than good.

Find a good machine shop that can tell you things about the LT1 most people don't know, like it's reverse cooled, the water pump is cam driven not belt driven, the rods are powdered metal and would cost only ~$80 more for a forged set than to recondition the stock ones after you factor in the cost of ARP hardware, etc. Make sure that machine shop uses a tq. plate for boring and line honing etc. And get a 3 plane balance done on the rotating assembly.

mhslax6

Thanks for the info! How do you like your cam?

hrcslam

It doesn't have as much power as it did stock under 2K rpms, but it's very drivable between 1500-2000 rpms. I can cruise in 6th at 45mph without any bucking with my stock 3.42's, but I can tell the engine doesn't like it. From 2-4K it's a noticeable jump, and from 4-redline it's like whoa!


Here's my dyno chart. This guy got me some nice numbers, but the tune was all wrong for daily driving, so I've redone most of it. I need to take it back to him to re-do the PE tune.

I'm not sure how close your cam will be to mine in the curves though, that all depends on the valve timing events.

mhslax6

I was going to do 4.10's right after I get it back together.

hrcslam

I'd love to do 4.10s but I can't justify any money going into the stock 7.5" 10 bolt. Saving up some funds to do a stronger rear instead. For now it's street tires and easy launches.

hrcslam

Ohh yeah, I was browsing Craigslist and found this. I don't need it, but it should work for your car. It's hard to find tuning software for OBD2 LT1's and this guys selling one in El Mirage.

http://phoenix.craigslist.org/wvl/pts/4582741421.html

$300 isn't too bad for everything in the ad, but maybe he'll sell the tuner program separately for less? Eh, thought I'd let you know.

mhslax6

Thanks, I appreciate the help!! I'll check that guy out.

mhslax6

Well not finding any serious buyers for the Vortech, so I will probably have to use it. I'm doing forged pistons and rods (doing a 355), so what else needs to be upgraded for boost. Will my cam and heads setup be ok? I'll obviously check with Lloyd first but I'm a couple months out on heads and cam....

hrcslam

When you do pistons, find a set that keeps the quench tight, but also reduces compression ratio. The dish should basically mirror the combustion chamber of the head, but as close to the center of the piston as possible.

As for the cam, I'd talk to Lloyd or AI.