LT5 383?

[vermatrix]

Can i take a 1991 and stroke it out to 383 without breaking the bank? What would I see in gains? Would love to see 500 or so RWHP?

Any ideas? TY

[Paul Workman]

Originally Posted by vermatrix

Can i take a 1991 and stroke it out to 383 without breaking the bank? What would I see in gains? Would love to see 500 or so RWHP?

Any ideas? TY

Ideas? Yes.

Porting, headers, SW X-pipe, phased cams can get you to 510 chp on STOCK cams and stock block.
"383" is synonomous with the std 350 cid SBC mated with a 400 cid SBC's crank (i.e., stroked).
The LT5 has been sleeved to 378, 380, 385, and most recently to 391 cid with the stock crank. 402s to 441 cid LT5's have been done with combination of bore/stroked and either a drop-in (CNC'ed) sleeve gang or closed deck conversion.

I don't know what you call reasonable (price wise), but except for modest 378 cid conversion, upping the displacement of an LT5 is typically a custom job: not a project where you go to a dealer and order up components off the shelf. (Expensive...in other words!)

What specific mods do you have in mind?

[vermatrix]

OK so first, you are obviosly light years above me with knowlege of this. I feel a little foolish.

I am not trying to build a fire breathing beast. In the past I had a few corvettes, now I want to get my ZR1 forever car. Would be a daily driver, for pleasure only, during the summers only. I live in Northern Wisconsin so probably about 6 months out of the year max.

All that being said, I want it to be crazy fast, drooling to look at and fun. Not sure what HP and TRQ numbers equal that. I remember back in the 90's stroking your SBC to 383 seemed to be the thing. I know the LT5 is not just another SBC, but trying to scope out my options.

I was anticipating spending around $6000 or so on her per winter, right now its going to be a 1991.

[TX '90 ZR1]

I take it that you do not have your Z yet?
When you find the "one", go over it and make sure all the basics (fuel,air & fire) are working properly. A stock, well tuned Z is still pretty impressive!
If you want more, start with the low hanging fruit (horsepower). There is a good bit of additional performance to be had for a relatively small amount of dollars.
My '90 was bone stock. All I have done performance wise is a Haibeck "chip", Corsa exhaust, and modified air intake. The difference is noticeable and I can put it back to bone stock in less than a couple of hours.
It has more power than I can reasonably use on a daily basis. More is always better in my mind, but weighing dollars to usability I am good. (For now!)
You can go to gear changes, headers, porting, etc., but I would recommend the "easy" stuff first and see where you are.
My opinion and worth exactly what it cost !!!!!

[Ccmano]

Originally Posted by vermatrix

I know the LT5 is not just another SBC, but trying to scope out my options.

The LT5 is in no way, shape or form a SBC. They share no parts in common especially not the block or heads. A completely different animal. That said, this is a common misunderstanding for those new to the “beast”. Its great that your gaining an understanding and knowledge before you jump in. Paul has already outlined the current possibilities of which there are many, the higher end of which can run in to 10’s of thousands of dollars. If your interested in an enhanced version, in my opinion, any of the Haibeck iterations are fantastic based on your wallet size. The best “bang for the buck” currently appears to be “Pete’s” 391 with an output of about 600hp. Check them all out and as Paul said, 500hp is within relatively easy mods and reasonable expense.
Have fun, keep us posted.
H

[Paul Workman]

Originally Posted by vermatrix

OK so first, you are obviosly light years above me with knowlege of this. I feel a little foolish.

I am not trying to build a fire breathing beast. In the past I had a few corvettes, now I want to get my ZR1 forever car. Would be a daily driver, for pleasure only, during the summers only. I live in Northern Wisconsin so probably about 6 months out of the year max.

All that being said, I want it to be crazy fast, drooling to look at and fun. Not sure what HP and TRQ numbers equal that. I remember back in the 90's stroking your SBC to 383 seemed to be the thing. I know the LT5 is not just another SBC, but trying to scope out my options.

I was anticipating spending around $6000 or so on her per winter, right now its going to be a 1991.

I was fussing with SBCs since the 60s, and built a clone L88. But, none of that impressed me as much as the potential hidden in the DOHC/LT5!

For example, this is my "508" hp LT5 (since tweaked a little more). Stock idle, ALL of the accessories work in heavy traffic. You would never know there was a monster hiding under the hood. But, with reground cams and sleeves it becomes a real beast. You've never experienced the torque curve of a DOHC motor, have you? Once you do, you'll likely notice how "peaky" any SBC really is!

https://www.youtube.com/watch?v=y1YFa8ruh8A

[vermatrix]

Originally Posted by Paul Workman

I was fussing with SBCs since the 60s, and built a clone L88. But, none of that impressed me as much as the potential hidden in the DOHC/LT5!

For example, this is my "508" hp LT5 (since tweaked a little more). Stock idle, ALL of the accessories work in heavy traffic. You would never know there was a monster hiding under the hood. But, with reground cams and sleeves it becomes a real beast. You've never experienced the torque curve of a DOHC motor, have you? Once you do, you'll likely notice how "peaky" any SBC really is!

https://www.youtube.com/watch?v=y1YFa8ruh8A

Paul,

Thank you for your insights. As I will be having my local speed shop do the work, How would I order this up? Ask them to regrind the cams and sleeves and they know where to go from there? Is that going to run me more then 6K?

Yes this will be my first ZR1. I am really looking forward to it.

[WARP TEN]

Originally Posted by vermatrix

Paul,

Thank you for your insights. As I will be having my local speed shop do the work, How would I order this up? Ask them to regrind the cams and sleeves and they know where to go from there? Is that going to run me more then 6K?

Yes this will be my first ZR1. I am really looking forward to it.

I would like to discourage you from having your"local speed shop" do this kind of work on an LT5. The LT5 is a special engine that many, many "local speed shops" ruin. They simply lack the specialized knowledge that these require. There are several true experts on the engine, some within shouting distance of Wisconsin, who regularly build LT5s to be highly reliable high horsepower engines. Pete was mentioned above as producing a good value 391, and of course Marc Haibeck (www.zr1specialist.com) has done hundreds of LT5s, his only business. Marc is in Addison Illinois and is always willing to talk with people interested in doing something with the 90-95 ZR-1s. His website includes a variety of options for LT5 upgrades and also provides prices for all the work. Pete is located nearby Marc in Illinois and has done very fine work on LT5s for many years. Both are good guys worth talking with before making any decisions.--Bob

[Ccmano]

Originally Posted by WARP TEN

I would like to discourage you from having your"local speed shop" do this kind of work on an LT5. The LT5 is a special engine that many, many "local speed shops" ruin. They simply lack the specialized knowledge that these require. There are several true experts on the engine, some within shouting distance of Wisconsin, who regularly build LT5s to be highly reliable high horsepower engines. Pete was mentioned above as producing a good value 391, and of course Marc Haibeck (www.zr1specialist.com) has done hundreds of LT5s, his only business. Marc is in Addison Illinois and is always willing to talk with people interested in doing something with the 90-95 ZR-1s. His website includes a variety of options for LT5 upgrades and also provides prices for all the work. Pete is located nearby Marc in Illinois and has done very fine work on LT5s for many years. Both are good guys worth talking with before making any decisions.--Bob

Omg! Take Bobs advice! For this kind of work you have no idea of the horror stories over the years from folks who took a Z to the local speed shop, Corvette shop, a trusted auto shop used for years or even a Chevy Dealer. You may actually find that many shops refuse to work on them. There is a listing with contact info of known national shops at the top of the general (this) section. Your in WI with easy access to Marc and Pete, they are the best.
H


http://www.zr1.net/forum/showthread.php?t=28634

[TX '90 ZR1]

Originally Posted by WARP TEN

I would like to discourage you from having your"local speed shop" do this kind of work on an LT5. The LT5 is a special engine that many, many "local speed shops" ruin. They simply lack the specialized knowledge that these require. There are several true experts on the engine, some within shouting distance of Wisconsin, who regularly build LT5s to be highly reliable high horsepower engines. Pete was mentioned above as producing a good value 391, and of course Marc Haibeck (www.zr1specialist.com) has done hundreds of LT5s, his only business. Marc is in Addison Illinois and is always willing to talk with people interested in doing something with the 90-95 ZR-1s. His website includes a variety of options for LT5 upgrades and also provides prices for all the work. Pete is located nearby Marc in Illinois and has done very fine work on LT5s for many years. Both are good guys worth talking with before making any decisions.--Bob

I'm going to chime in here and advise you take Bob's advise. As has been said, this is not the old SBC we used to work on. In fact, it is not a SBC!!