I got that 4 bolts block from a 1998 GMC van. It's a L31 vortec option. Now I discover from my GM dealer that the engine rod are the same as the one in an LT4. My projet is to have near 400 hp to the motor with enough torque to keep my 3.07 gear with my TH350C for now(a manual trans later). I want to order some speedpro TRW forged piston ,a Comp cam XR-270, an Edelbrock performer Air gap and some 1,5 self-guiding roller rocker.

Before I go ahead, any comment on any of these parts?
Does the performer air gap has near the stock height because I want to keep the stock air filter?
Anybody runs the comp cam XR-270?

Thanks a lot.

Here a pic of my block after the visit to the machine shop.




[Modified by American Boy, 11:55 PM 9/3/2002]

 

Should be the same block as the ZZ4 block. Good block, good rods.
XR264 is one step below XR270. 270 should be great for a street engine. It's the hydraulic roller variant of the XE262.

I just realized that it's the ZZ4 block a while ago, and am beginning to rethink getting a brand new block... ;)

You have a very good foundation there!

-Steve

 

Sounds like you have a nice foundation to work with. :yesnod:
Forged pistons are probably the best but do you really need them? You could save some money if you went with hyperuectic pistons.
Are you going to run nitrous oxide in the future?

I'm pretty sure that the air gap intake will NOT fit under your hood.
What heads and exhaust are you going to use?
What are some of your future upgrade plans?

ttt



[Modified by MIKER, 5:01 PM 9/4/2002]

 

(Pacin' California)
I didn't know it was the ZZ4 block. That block had 130000 miles on it and the cylinder wall were really nice. In fact, after honing the cylinder, it has only 0,0015 inch of wear. My machinist said to me that the added clearence would be perfect for forged piston.

(Miker)
Actually the forged piston come at a really nice price, 224$ for the set. I think it's similar pistons that were used in L82 engine (TRW). The big quantities should explain the price...maybe. Yes this engine will use a 75 or 100 hp nitrous later in it's final configuration. If the performer air-gap don't fit, I'll lose the air gap. The heads are the Vortec. They already have a 3 angles valve job on them so I'm confident that they'll flow enough to take the hp up to 400 at the engine. The exhaust will be dual no cats with some dynomax ceramic headers and some dynomax ultraflow at the end. For the carb, I'm keeping my quadrajet because I think that there's isnt a best carb for a daily driven car when tuned properly.

Stephan

 

Yup, that does seem like a reasonable price for forged pistons! From what I understand, your better off with your well seasoned block than a new one because fresh castings "move" around a lot until they settle in. I've heard that some race engine builders will use a block in their tow vehicles for a period of time to take advantage of the heating and cooling cycles. It supposedly has the same affect as cyrogenically (sp?) treating a block to relieve casting stress.
Vortec heads will certainly meet your needs. I almost used a pair for my engine buildup.
You are aware of their limited lift capacity in stock form I presume!?!
There's been a LOT of discussion about these heads. The link below is one of the recent threads. You've probably already seen it in the Engine Mods section.
vortec heads???
http://forums.corvetteforum.com/zero...886152#3886152

 

Forged pistons can be cheaper than hypereutectics, depends on manufacturer..

Biggest problem with forged is that they don't seal as well as aluminum or hypereute.

Ask Paul79 about oil burning. :)

They are definitely more formidable than the other pistons, but hypereutes should be able to stand up to a 75-100 shot. More would be doubtful.

Real engine builders should know more than me, you should post about hypereutes versus forged.

-Steve

 

A 400 horse roller cammed junk yard block you say:

http://www.chevyhiperformance.com/ed... viewtype=text

Might give some ideas. ;)

 

(Miker)

That's great info. I heard about the lift limitation but after mesuring the distance bethween the retainer and the valve seat, I get 0,710''. I don't have the valve seal anymore but they should reduce the clearence near 0,200'' leaving around 0,500''. So I wonder if we can use a different valve seal to eliminate that problem or simply take the head to the machine shop to shave the valve guide.

Another thing is the valve spring. I found that Scoggin-Dickey offer direct fit spring to accomodate 0,550'' lift cam on the vortec head at 50$. http://www.sdpc2000.com/cart.asp?act...2060&pid=81626

(Pacin'California)
Thanks, I'll check on that. A friend runs TRW forged on his mustang with 12,6 ET times and he uses his car daily so I'll ask him about the oil consmuption.

(Fevre)
Yeah, I didn't realise how much of a deal that engine was until I bought it. The approximate cost of the total engine ready for the swap will be near 3000$ canadian or 2000$ us. The thing about these motor is that there's some components that don't fit like the oil pan, valve cover, fuel pump. I'll have to buy them used to keep the cost down.

Stephan

 

I don't know if there is a different valve seal that would solve the problem or not.
Adam, in the Engine Mods, vortec thread said "Comp Cams make a conical spring that allows a higher lift and spring poundage without machining the pockets. Seems to be about $10-20 more than regular springs/keepers, etc. They are about $115."

A friend of mine had the valve guides machined for additional clearance and used some new Comp Cams springs. I don't know the details about the springs he used.
I've heard that you can buy a tool that enables you to machine the valve guides down yourself, "at home".

Either way, post any new information that you find out with regard to using the Vortec heads. It's always good to get solid information from those who are actually using them.

 

You are going to end up with a really good engine! Basically a iron headed ZZ-4 (if you use the Vortecs) You should have no problem getting 400 hp with that engine. I was looking for a suitable Vortec short block to go with my Vortec heads before I bought my ZZ4.
The Scogging Dickey springs sound like a good deal at $50, Comp cams makes some tools to allow you to widen the spring seats and to cut down the valve guides, the tools and the mandril cost about $100.00, then you have to use a 3/8" drill to "do it yourself" The $50 springs sound like a good deal, plenty of lift and no "do it yourself."
Good Luck!
Good luck!