GTP CompG with L26 Bottom HELP!!!!!

**jewell83** · 01-26-2014

Hello every one!! I am new here I have a question and need some professional opinions!! I just traded my 96 Z28 for an 04 Grand Prix GTP Comp G. The guy that I traded to put a L26 bottom end only in place of the L32 bottom end due to a burned piston. I know the L26 has flat top pistons and the L32 has dish. I have to pull the heads he told me it had a warped or cracked head it was getting coolant in #4 cylinder. Will I have any issues with compression or issues with it blowing gaskets? If the heads are cracked or warped what would you guys suggest I do. When I get the heads fixed and back on will I have to have my car tuned. I am in need of some good information if some one could HELP ME IT WOULD REALLY HELP ME OUT.. THANKS

**machinegunsquid** · 01-26-2014

Once you pull the heads take them to a good machine shop and have them check them out. They should be able to deck the heads and get them flat if they aren't too warped.

Also, once the heads are off, clean the block really well then put a flat edge on it to make sure the block isnt warped.

If you can get the heads back in spec and the block is okay, no reason for it to leak as long as you reinstall everything correctly.

**jewell83** · 01-26-2014

Thanks do think I will be ok with the flattop pistons?

**Slick2500** · 01-26-2014

I don't remember the piston tops being any different. The only thing I think is different is the compression ratio. The tops of the pistons look exactly the same on my L67 as they do on my L26.
If its still on the stock pulley I would run a step colder plug and try to get a downpipe. And run the highest octane gas you can.

**Scottydoggs** · 01-26-2014

the block is fine. its a top swap basically, it gets done all the time.

as long as your tearing into it, this would be a good time to add headers. a top swap needs to exhale a bit better. they will make the engine happier. the old block was low compression, this new block is hi compression.

sounds like a good trade too.

**jewell83** · 01-26-2014

Thanks Im going to look for some headers online sounds like a good idea. That's great I was super worried I would end up pulling it out and starting from scratch. That sure gives me some peace of mind LOL. Yeah the GP is really nice I have had z28s all my life I think I am ready for something new. THANKYOU FOR THE REPLYS GUYS!!!

**timboku** · 01-26-2014

I have an l26 with a Gen 3 and L67 Heads. All good. Just get headers to let it breath and run 93 octane. I had no KR on a stock pully. Its a top swap thats all.

**FASGP** · 01-27-2014

I run L26 with L67 heads and GenV on top. Just check the surfaces, and redo proper gaskets on the top half, and you should be golden. The L26 makes a real nice difference over the L32 or L67 bottom end...so enjoy that. Welcome to the 3800 family...

**crbquist** · 01-27-2014

Originally Posted by FASGP

I run L26 with L67 heads and GenV on top. Just check the surfaces, and redo proper gaskets on the top half, and you should be golden. The L26 makes a real nice difference over the L32 or L67 bottom end...so enjoy that. Welcome to the 3800 family...

I'd run an l67 or l32 over an l26 any day. Not sure what is so special about an l26... Just a cheaper solution when replacing a 3800.

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**tomtom123** · 01-27-2014

^ The difference is compression ratio. The L67 and L32 is like, (someone will probably have more accurate numbers), 8.5:1 compression ratio whereas the L26 is something like 9.0:1? The higher compression gives you more power. The L26 stock will lose to an L67 or L32 that's stock, but if you took the L26 bottom end, with the higher compression ratio, and top swapped your blower on top, you how have a high compression ratio'd supercharged monster. A topswapped L26 will put down more power than a lightly modded L67. That's why a lot of people like to topswap their L67's/L32's onto the L26 bottom end.

**timboku** · 01-27-2014

L26s are way cheaper snd easier to find with low miles...as well and makes more power topped swapped.

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**crbquist** · 01-27-2014

I am well aware of the different compression ratios, however I disagree with the power differences. Sure an L26 will make slightly more power than an L32/67 with a stock pulley given the tune is good and there is no KR. When you get down to the 3.0 pulley range on an L32/67 running safety, you'll be in the 3.4 pulley range with an L26 (unless running e85), hence making less power even with higher compression. Bottom line is the supercharged bottom ends can handle more boost and take more abuse than the weaker rodded N/A bottom ends. Plenty of guys have made great power with the L26, and many of them have blown up in doing so... I'd much rather take reliability over trying to squeeze every last bit of hp out of a ticking time bomb.

**sseilmnop** · 01-27-2014

2 years and still ticking.

**FASGP** · 01-27-2014

1.5 yrs on a tuned 3.2 pulley Gen V and still ticking. I have built all three types, and disagree. The L26 has felt the strongest by far.

**sseilmnop** · 01-27-2014

Originally Posted by sseilmnop

2 years and still ticking.

Gen 5
Intercooler (phenolic)
Headers
VS Cam
N*
3.2 (need bigger injectors)

**crbquist** · 01-27-2014

I know people have run them with great success and made good power. I just wouldn't trust one on a high hp build over an L67 or 32. I've heard of too many horror stories. If I somehow managed to blow my original L67 I'd probably look for another L67 or 32 over an L26 or 36. The supercharged bottoms are much more KR forgiving than the NA bottoms. Just my opinion and preference.

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**sseilmnop** · 01-27-2014

Originally Posted by crbquist

I know people have run them with great success and made good power. I just wouldn't trust one on a high hp build over an L67 or 32. I've heard of too many horror stories. If I somehow managed to blow my original L67 I'd probably look for another L67 or 32 over an L26 or 36. The supercharged bottoms are much more KR forgiving than the NA bottoms. Just my opinion and preference.

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He has a top swap (bottom swap) and maybe adding headers.

This is not a high HP build.

It's a get it running build.

**crbquist** · 01-27-2014

Originally Posted by sseilmnop

He has a top swap (bottom swap) and maybe adding headers.

This is not a high HP build.

It's a get it running build.

I know that, I meant in general. Regardless, I'd still opt for an l67 or 32. Just my cup of tea..

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**sseilmnop** · 01-27-2014

Originally Posted by crbquist

I know that, I meant in general. Regardless, I'd still opt for an l67 or 32. Just my cup of tea..

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You are recommending throwing away his current motor and starting over with used L67 L32 motor. Have you looked and priced one lately?

They want $1,500 for one with 150,000 miles.