new ZL1 block. advises?
Thread Starter
Burning Brakes
Joined: Sep 2008
Posts: 753
Likes: 0
new ZL1 block. advises?
Ok , I can't stop an oil leak at cyl 5 on my 427 L88 type...it should be an oil ring or worn cyl wall ( the bore has a ridge at the top, bores are already at + 030.)
If I have to take the engine out, just thinking to go for a GMPP ZL1 block 12370850. the $5000 price is not too bad.
does someone have any experience on this Alu block? can I move all the parts from my engine to this block?I already have the GMPP alu heads -the 572 cid type
reliability problems?
of course if someone has one of these ZL1 blocks at better price...
and i can always resell my block to get back some $$$ : it's a 68 CE replacement block
any advise is welcome , as usual
Aldo
If I have to take the engine out, just thinking to go for a GMPP ZL1 block 12370850. the $5000 price is not too bad.
does someone have any experience on this Alu block? can I move all the parts from my engine to this block?I already have the GMPP alu heads -the 572 cid type
reliability problems?
of course if someone has one of these ZL1 blocks at better price...
and i can always resell my block to get back some $$$ : it's a 68 CE replacement block
any advise is welcome , as usual
Aldo
Race Director
Joined: Jan 2000
Posts: 13,018
Likes: 2,262
From: Corsicana, Tx
2020 C2 of the Year - Modified Winner
2020 Corvette of the Year (performance mods)
C2 of Year Winner (performance mods) 2019
2017 C2 of Year Finalist
You could easily bore it to .060" plenty of room.
If I was looking at aluminum blocks I'd be looking to Dart etc for some real meat in them.
JIM
If I was looking at aluminum blocks I'd be looking to Dart etc for some real meat in them.
JIM
Thread Starter
Burning Brakes
Joined: Sep 2008
Posts: 753
Likes: 0
I want to reuse everything of my engine, pistons included.
so if I have to restore the block I have , I would work only on the bad cylinder bore : bore it and sleeve at + .030.
the other cylinder bores are OK and the engine has really few miles on it but something went wrong just at fifth cyl.
If I go for a an aluminum block I would stay with GMPP just because of the brand...and don't go too far away from the original L88 project where I started. I would use all the genuine L88 parts I have in my engine ( dimple rods, L88 pushrods, L88 -Zl1 cam , flat tappet, GM steel crank...)
I'm new to Dart as brand , I'll get infos...
Terrorizing Orange Cones
Joined: Oct 2007
Posts: 2,572
Likes: 17
From: Northern CO
Le Mans Master
Joined: Oct 2006
Posts: 7,123
Likes: 433
From: Gladstone MO
C3 of Year Finalist (appearance mods) 2019
If you can find the GMPP aluminum block. From what I've heard they sold pretty fast after the release.
Look at Dart and Brodix if you're serious about an aluminum block. Tougher stuff.
I'd find out what's going on with #5. Could be that the guy that assembled it missed the ring gaps or stacked an oil ring.
Look at Dart and Brodix if you're serious about an aluminum block. Tougher stuff.
I'd find out what's going on with #5. Could be that the guy that assembled it missed the ring gaps or stacked an oil ring.
Corvette Stories
The Best of Corvette for Corvette Enthusiasts
Top 10 Most Expensive Corvettes Ever Sold on Bring A Trailer
Brett Foote
10 Things Every Corvette Owner Needs (2026 Edition)
Michael S. Palmer
8 Most "Only Corvette Owners Understand" Quirks and Problems
Pouria Savadkouei
10 Reasons the C6 Z06 is Still A Performance Benchmark After 20 Years
Joe Kucinski
How Much Horsepower Every Corvette Engine "LOST" in 1972
Joe Kucinski
Top 10 DOs and DON'Ts for Protecting Your Convertible Top!
Michael S. Palmer
Top 10 Most Explosive Corvettes Ever Made: Power-to-Weight Ratio Ranked!
Joe Kucinski
150 hp to 1,250 hp: Every Corvette Generation Compared by the Specs That Matter
Joe Kucinski
8 Coolest Corvette Pace Cars (and Replicas) of All Time
Verdad Gallardo
Safety Car
Joined: Nov 2008
Posts: 3,720
Likes: 557
From: Seattle Washington
I'm useing a GM Aluminum Block although its a Small Block and not a Big Block. My engine builder said it was the Best Block He has ever used no Grinding to assemble the Engine. Most aftermarket Blocks require a test fit to see what rubs and then some Grinding and then Assemble and find something more to be gound and then the same thing all over again. My GM Block was manufactured by March Performance if I remember right. 5k is an exspensive way to save 40lbs, but there is nothing like having an all Aluminum Engine.
Le Mans Master
Joined: Dec 2006
Posts: 5,557
Likes: 9
From: Oquirrh Mountains
St. Jude Donor '09
Jim
I want to reuse everything of my engine, pistons included.
so if I have to restore the block I have , I would work only on the bad cylinder bore : bore it and sleeve at + .030.
the other cylinder bores are OK and the engine has really few miles on it but something went wrong just at fifth cyl.
If I go for a an aluminum block I would stay with GMPP just because of the brand...and don't go too far away from the original L88 project where I started. I would use all the genuine L88 parts I have in my engine ( dimple rods, L88 pushrods, L88 -Zl1 cam , flat tappet, GM steel crank...)
I'm new to Dart as brand , I'll get infos...
I want to reuse everything of my engine, pistons included.
so if I have to restore the block I have , I would work only on the bad cylinder bore : bore it and sleeve at + .030.
the other cylinder bores are OK and the engine has really few miles on it but something went wrong just at fifth cyl.
If I go for a an aluminum block I would stay with GMPP just because of the brand...and don't go too far away from the original L88 project where I started. I would use all the genuine L88 parts I have in my engine ( dimple rods, L88 pushrods, L88 -Zl1 cam , flat tappet, GM steel crank...)
I'm new to Dart as brand , I'll get infos...
http://www.gmpartsdirect.com/results...row=6&pkgid=67
P/N: 25534362
(boy, I'm full of good advice tonite!)
Thread Starter
Burning Brakes
Joined: Sep 2008
Posts: 753
Likes: 0
the idea to restore my block is not very exciting...pull it out, do the job, repaint...just to fix a broken thing. If I'll decide for it , I'll delay the thing to winter for sure.
Instead I'm so amazed by the aluminum block idea, that I would start tomorrrow...but better to take a little time
I know that with an alu block I'll loose power , but being "european" I'm more intrigued by the weight loss than power. the GMPP alu block is not the stronger ( Dart, brodix....are a bit heavier but surely stronger) but weights just 110lbs. I would save 160lbs on the front of my car. I think the car would handle as I would like.
BTW, if I decide to keep the iron block I have, what's best to do and why?
please consider that just 1 cylinder bore is tapered, the others not. the engine has few miles and bores are already at + .030
1) bore and sleeve the bad cylinder bore ,reuse the .030 pistons ( unless I find then faulty)
2) bore the 8 cylinders to .060 and buy new pistons
Instead I'm so amazed by the aluminum block idea, that I would start tomorrrow...but better to take a little time
I know that with an alu block I'll loose power , but being "european" I'm more intrigued by the weight loss than power. the GMPP alu block is not the stronger ( Dart, brodix....are a bit heavier but surely stronger) but weights just 110lbs. I would save 160lbs on the front of my car. I think the car would handle as I would like.
BTW, if I decide to keep the iron block I have, what's best to do and why?
please consider that just 1 cylinder bore is tapered, the others not. the engine has few miles and bores are already at + .030
1) bore and sleeve the bad cylinder bore ,reuse the .030 pistons ( unless I find then faulty)
2) bore the 8 cylinders to .060 and buy new pistons
Last edited by elle88; Jul 9, 2009 at 04:53 PM.
Melting Slicks
Joined: Apr 2002
Posts: 2,337
Likes: 14
From: Norfolk VA
5k for a hunk of metal designed to 60's specs. You are simply paying for the" ZL-1 name. If you choose to go with an aluminum block I too would go with Dart, brodix. On the other hand if you are going to use the same internals I would look into the cause of the oil leak. Much cheaper than the ZL-1 block, especially if you are using the same internals. Either route you choose, good luck.
Tech Contributor
Joined: Jun 2004
Posts: 20,910
Likes: 962
From: I tend to be leery of any guy who doesn't own a chainsaw or a handgun.
the idea to restore my block is not very exciting...pull it out, do the job, repaint...just to fix a broken thing. If I'll decide for it , I'll delay the thing to winter for sure.
Instead I'm so amazed by the aluminum block idea, that I would start tomorrrow...but better to take a little time
I know that with an alu block I'll loose power ,I hear that quite often, and I don't necessarily dispute it, but I've never seen an A-B comparison to see how signicant that difference actually is. but being "european" I'm more intrigued by the weight loss than power. the GMPP alu block is not the stronger ( Dart, brodix....are a bit heavier but surely stronger) but weights just 110lbs. I would save 160lbs on the front of my car. I think the car would handle as I would like. The new block is a slight improvement over the old one (Not 60's technology, as some claim. The original ZL1 block was 90 pounds. The new is 110 pounds, as you mentioned.) I'm going with the new block in my '69. The 160# reduction in weight is about a 5% reduction in total vehicle weight, and it's essentially all off the front.
BTW, if I decide to keep the iron block I have, what's best to do and why?
please consider that just 1 cylinder bore is tapered, the others not. the engine has few miles and bores are already at + .030
1) bore and sleeve the bad cylinder bore ,reuse the .030 pistons ( unless I find then faulty)
2) bore the 8 cylinders to .060 and buy new pistons
Instead I'm so amazed by the aluminum block idea, that I would start tomorrrow...but better to take a little time
I know that with an alu block I'll loose power ,I hear that quite often, and I don't necessarily dispute it, but I've never seen an A-B comparison to see how signicant that difference actually is. but being "european" I'm more intrigued by the weight loss than power. the GMPP alu block is not the stronger ( Dart, brodix....are a bit heavier but surely stronger) but weights just 110lbs. I would save 160lbs on the front of my car. I think the car would handle as I would like. The new block is a slight improvement over the old one (Not 60's technology, as some claim. The original ZL1 block was 90 pounds. The new is 110 pounds, as you mentioned.) I'm going with the new block in my '69. The 160# reduction in weight is about a 5% reduction in total vehicle weight, and it's essentially all off the front.
BTW, if I decide to keep the iron block I have, what's best to do and why?
please consider that just 1 cylinder bore is tapered, the others not. the engine has few miles and bores are already at + .030
1) bore and sleeve the bad cylinder bore ,reuse the .030 pistons ( unless I find then faulty)
2) bore the 8 cylinders to .060 and buy new pistons
Le Mans Master
Joined: Oct 2007
Posts: 6,007
Likes: 1,746
From: Richmond Kentucky
2025 Corvette of the Year Winner- Modified
2024 C2 of the Year Winner - Modified
2022 Corvette of the Year Finalist -- Modified
2021 C2 of the Year Winner - Modified
2021 C1 of the Year Winner - Modified
2020 Corvette of the Year (stock)
C2 of Year Winner (stock) 2019
2017 C1 of the Year Finalist
Recently installed one in my 67 and I like it just fine, NO, I LOVE IT! Bought it one piece at a time, brand new block from a machine shop before they did any work to it, got a good deal on it. Then bought all the other parts as I found them available on the internet, ALL new, ALL GM parts at a good price. I say go for it!
Rex
Rex
Melting Slicks
Joined: Jun 2003
Posts: 2,802
Likes: 241
From: Niles, MI
Recently installed one in my 67 and I like it just fine, NO, I LOVE IT! Bought it one piece at a time, brand new block from a machine shop before they did any work to it, got a good deal on it. Then bought all the other parts as I found them available on the internet, ALL new, ALL GM parts at a good price. I say go for it!
Rex
Rex
Le Mans Master
Joined: Oct 2007
Posts: 6,007
Likes: 1,746
From: Richmond Kentucky
2025 Corvette of the Year Winner- Modified
2024 C2 of the Year Winner - Modified
2022 Corvette of the Year Finalist -- Modified
2021 C2 of the Year Winner - Modified
2021 C1 of the Year Winner - Modified
2020 Corvette of the Year (stock)
C2 of Year Winner (stock) 2019
2017 C1 of the Year Finalist
Sorry, didn't mean to hijack ELLE88's post. Unfortunately the ZL-1 is not a product of TRACO, but this one is................I was originally going to "de-tune it" and put it in my 67 and then the ZL-1 came along, so......................the Traco engine had to wait a while longer for its new home, but someday....................
Le Mans Master
Joined: Dec 2003
Posts: 5,727
Likes: 38
From: Fremont CA
The GMPP block was made due to demand by vintage Can-Am racers for a replacement of their aging ZL-1 parts. There are soemadvantages to using a Dart, Brodix, Rodeck blocks are all stronger pieces that even the later design GMPP aluminum big block. The iron block in you L-88 would probably accomodate a 0.100 to 0.125 (2-3MM) overbore based on it being a 4 bolt main HP factory block (they usually have pretty thick cylinder walls on the 4 bolt castings.) The block can be checked with a sonic tester for casting thickness by a racing engine rebuilder. Iron engine blocks have been know to be more stable and will generally make more power than a aluminum motor. One advantage to going to a aftermarket engine block would be the ability to make a 4.40" (111mm) bore motor with ashort stroke crank. Back in the 60's Bruce McCLaren was testing the 510cu/in Can-Am Chevy motor (went over 212MPH at Riverside raceway in Los Angeles, CA) and demanded they replace that "monster" with his much preferred 4.40 boreX3.5625 stroke 430 motor that he ofeten said was his favorite Can-Am motor.
Thread Starter
Burning Brakes
Joined: Sep 2008
Posts: 753
Likes: 0
I'm quite sure... Zl1
now I have to find $$$ quickly ( I don't have the $$$ tree! ) because I would like to do the job in august ( too hot here for enjoing a BB car ) and have everything ready by early september.
I think I can sell the 68 block and get back some $$$ too. does someone have an idea of the market value of my block? 1968 CE852797 marked replacement block , 4 bolts, +0.30 . I can't find any on ebay to have just an idea...
but I could keep the block too for other projects...
so Solid LT1 , the problem of sleeving a cylinder bore is to have enough meet to overbore , right? Hmmmm you make me think...just in past days a friend of mine has sleeved 2 cylinder bores on a 454 2 bolts , but he has bored more than what you say being safe and then bored the sleeves to +0.30 . there was a cyinder crack in one cyl , the other had a small hole. should my friend fear possible engine failure?
now I have to find $$$ quickly ( I don't have the $$$ tree! ) because I would like to do the job in august ( too hot here for enjoing a BB car ) and have everything ready by early september.
I think I can sell the 68 block and get back some $$$ too. does someone have an idea of the market value of my block? 1968 CE852797 marked replacement block , 4 bolts, +0.30 . I can't find any on ebay to have just an idea...
but I could keep the block too for other projects...
so Solid LT1 , the problem of sleeving a cylinder bore is to have enough meet to overbore , right? Hmmmm you make me think...just in past days a friend of mine has sleeved 2 cylinder bores on a 454 2 bolts , but he has bored more than what you say being safe and then bored the sleeves to +0.30 . there was a cyinder crack in one cyl , the other had a small hole. should my friend fear possible engine failure?
Last edited by elle88; Jul 10, 2009 at 06:26 AM.