Okay so about a year ago this time I was looking for a fuel pump for my truck. After taking my sweet time (about six months), I finally bit the bullet and purchased a magna fuel 4303 Pro Tuner 750. Long story short - I shot a rod through the oil pan TWO days before it came in! This happened about six months ago and I am long overdue to get this truck back on the road.

The turbo is a PT76/75 CEA and I'm interested in your opinions of engine options. First and foremost, I could rebuild the blown up 6.0 into a forged 370 and it would make for a nasty street setup of 700-800rwhp. I'm unsure whether to use a local engine builder or someone who specializes in LS engines. Next would be to purchase a LSX-B15 which is GM's 6.2/376 crate engine with forged internals rated to 15lbs of boost. The forged 370 short block would run between $3k-$4k (assembled) and the LSX B15 long block retails around $7,600. I like the idea of having square port heads and a LSX block for a few thousand bucks more - not to mention a factory performance engine.

HERE'S THE TIRE KICKER…. I also know where I can get a LSX 427 (intake to oil pan) for $4,500. The engine is brand new, has never been ran, and owner has over $9k invested. Lunati pro billet crank, pro billet rods, L92 heads, inconel exhaust valves, and the list goes on. The negative is that it is currently disassembled because the crank has developed some surface rust on one journal. It will need to be turned or polished. All clearances were previously checked before it was assembled the first time and the owner thinks it would cost $500-$600 to repair and reassemble.

Obviously, it would make the most sense (current turbo wise) to get a forged 370 or possibly LSX-B15. The LSX-B15 would probably flow too much for the PT7675 but I believe I could make do for awhile. I will eventually want to push more power than the PT7675 is capable of just to keep up with my dad's truck which is a 76mm 6.0 s10 already running 10s on moderate boost/stock engine. I ultimately would like to upgrade to a T6 max effort single turbo such as the GT55 or Precision equivalent. Ideal scenario would be to buy the LSX 427 and run with my current turbo setup but the PT7675 would more than likely CHOKE the LSX 427.

I'm leaning more towards the LSX 427 because of the value but with so many options, I'm currently undecided on what to do. I'm trying to be extremely cautious because it seems like I've read at least one bad review on each engine builder/manufacture/company - from GM Performance Parts down to the regional LS builders. Advice or comments are greatly appreciated. Thanks in advance!

 

The b15 is a good deal for what it is... I always loved the idea of it but being supercharged I wanted a tad more compression.

The 427 sounds like a good deal. What block is it? That will really define how much abuse it can take more so than the internals.

 

The 427 has a true LSX block.

 

If you can build your own motor or have a reliable company near you that's a nice way to go.

How ever the B15 LSX is no joke for the money. Remember it's safely rated to 15 LBS of boost... Doesn't mean you can't get more out of it if it's tuned properly. Look at how far people have pushed the factory short blocks.

 

Good piece of info to know.... Gm only warranties those motors, B8 and B15, if you use the Gm performance torque converter behind them.


Those CEA 76/75 are some great turbos! I'd take $3000-$3,500 and build me a forged 370ci!

 

If it's an LSX that's what is buy no question

 

I vote 427

A small turbo on a big engine is fine, it will just peak early. You will probably make 1000ft/lb at 3800rpm or so with a 427 and 76mm, but probably 800hp or so at 5500rpm. No big deal, just get a bigger turbo later and shift earlier

 

Have ask yourself what you want

That price for a 427 is sketchy when parts cost alot....a 427 isnt in your league...i have twin billet 7675s for my 427

Your single 7675 will be small even for a 376, better off with a 370 or even a 5.7 for that turbo

Lsx376 is a bad **** with some upgrades done to it...cam swap, head studs and valve springs...the b15 does use l92 heads, it has 6bolt lsx ported heads

 

It's hard to find info on the LSX heads. George do you know anything about them?

I assumed they were the same as the LS3 heads but 6 bolt. Are they CNC'd?

I agree... B15 is a mad mother... and who doesnt love factory ****. As Joseph mentioned, look at what people accomplish with way lesser parts in say an LQ9.

 

They flow well numbers are out there, saw info on yellowbullet
Internals are similar to ls9/lsa, uses a ls3 cam


We have a project that will have a b15 with twin precisions on it..goal is 1100 which ahould be a cake walk on e85...plan to swap to arp studs