Hey guys, I am starting to wonder if my block is going to handle what I'm getting ready to do... The motor is fully built blah blah blah, a huge turbo is going in, what are the LT1 blocks that have 4 bolt splayed billet caps, and all ARP fasteners capable of handling?

For those of you that want to know.
The crank is a 4340 Cola 3.75 stroke (383ci) with 6" Pro I beam rods from Speed O Motive, and 8.5:1 JE pistons, a custom grind hydrallic roller cam that I'm now thinking is way to small (225/233 529/550 on a 114* ls and 1.52 CC Hi-Tech SS rockers), and LT4 AFR 210s fully worked by AFR for around 223 total CCs. On top is a fully ported LT1 intake matched to an LT4 gasket and a BBK 58mm TB


Any input on the cam specs? I'm told by a couple well know ford guys to go way bigger and solid roller. (I'm not buying $525 lifters!!!) Motor has been built for a few years now, I just ran out of money and time back then, so the project never got finished... Now I'm changing the combo from a little ol P600B to a big nasty single turbo and throwing out all the unecessary weight and ammenities!


I'm more or less a Honda guy after working on them for almost 13yrs, so its been a while since I have messed with my Z28 project I started back in '98! Dont be a hater... I still love my Chevy! One of the main reasons for getting back into the project is all the hell I get from my Honda/Acura customers, and how my Camaro will never run with the 10 sec. cars I build them.
Ha... we'll see! I can't wait for them to see a wheel stand past the 60' as I go by them! :-)

 

I can't think of anyone that's put a big thumper on an LT1.

How big you going? 91.5mm?

Zturbo may have one together, but I don't know if it's still LT1
BigRick is putting one together, but it's not done yet...

I decided to switch to an aftermarket block when I asked the same questions you are asking..

Cam specs depend completely on your "effort".. If you want a drivable car with minimal valve train maintenance, your cam will be ok. If you want max effort, your cam is WAY small

good luck! and glad to see you posting again, Randy

 

Sounds very similar to my combo. I went with a shorter rod, my cam is quite a bit bigger and I'm running a pair of hairdryers, but otherwise...

I'm interested to see how big the turbo is. A 91.5 is a BFT. ****, a large frame 88 is a BFT. If block strength is a concern, you can either switch to a Motown or Dart block, or try to gut it out with the LTx block and some block filler.

We're already taking bets in the shop on whether the block will kill itself.

 

it may, but then again it may not... we'll have to see, but I threw out all theories when I started making 700+ crank hp out of 4 cyl. aluminum 1.8L open deck Hondas! :-)

I went with the longer rod so I woud have a much better rod to stroke ratio and much less force on the piston skirt into the cylinder walls which we all know causes a short engine life.

I will probably go with a bigger cam later on, but I want to see what this one does first. Besides I already have way to much money in the motor as it is now.

 

mochanic- How much power are you shooting for. Is it 700, 800, 1000, or more? The factory blocks are stronger than most give them credit for. I say keep the cam small to run less RPM's and more boost. It seems like I remember Job Spetter or a car he drove a really long time ago with a first gen block and that turbo car made around 1300HP but I don't know how long it lasted.

 

1000hp to the wheels.

I agree, I think they can handle more than most people give them credit for. It really all just comes down to tuning after you get all the good parts.

One problem I think allot of people have is that they dont run sequential engine management that will allow you to adjust individual cylinder fuel and timing control. A big factor in a manifold like an LT1/LT4 with a big open plenum and short runners layed out like they are is that each cylinder is not equally filled with the incoming charge and therefore you may have a couple that run leaner than the majority of the them, which of course causes detonation and ends in engine failure.

 

1,000rwhp? What tranny you planning on using?

Rich Krause

 

a built powerglide.

 

Sounds reasonable, though I think you will find it annoying on the street and a TH400 might work out better.

Rich Krause

 

for the street it probably would, but like I said its 90% track, 10% street.
The glide uses up 18hp while the T400 is at leat 46hp depending on the components, not to mention its way heavier!

I was originally gonna put a 4L80E in it until I decided it was more of a race car than a daily driver... now thats a HP eatin heavy SOB!