i dont know too much about the differences. Go ahead and put a smaller pulley on it...see what happens

ok so if the the bottom ends of the L36 and the L67 are the same and if you do a top swap why then does the L36 have a higher compression? why does it have higher output then a slightly moded L67?

Ordonez is completely right. The L36 has the higher compression pistons, but the pistons in the L36 bottom end are VERY weak, and very detonation sensitive. They cannot handle knock as well as the GTP pistons, and if running with too much KR you'll be replacing your motor.

You can drop pulleys on top swapped, but from what I've seen you have to be much more careful, most people don't do the 3.4" on a top-swapped car unless they have cammed it, headers & DP, intake, Ported S/C, a good tune, and maybe a few other things. You just have to do the supporting mods for say a 3.2" pulley on a GTP in order to run a 3.4" or 3.5" knock free on a top swapped GT.

Having said that, I'm hoping that with my cam already in, I can do headers, then drop to a 3.5".

Taller pistons means higher compression.

If I'm not mistaken, some of the guys on ClubGP have gone with L36 short blocks after they chipped a piston.

Yep, however they are probably using built L36 shortblocks with better pistons... you can make more power because to put it simply, the higher the compression, the more efficient the engine, but when you throw boost into the mix, it's a whole different story.

Whippled L36... I wouldn't even try. I think that unless you got a built race motor with all new internals, you'll break those pistons faster than you wouldn't believe. You need to slow down though man, just take one thing at a time.

Both engines use a cast aluminum piston... As far as I know cast aluminum doesn't take kindly to detonation, period. Err go the reason that people like to see "0" KR. The more KR you see on your scanner, the closer you are to replacing a piston or two.

L36 and L67 uses the same exact crankshaft.

the differences are pistons and rods. L36 internals don't fail because they are "weaker" then the L67 components but because of the higher compression ratio to start with. On a top swap a 3.8" pulley on an L36 is in the neighborhood of the 3.4 on the L67. The pistons aren't any more prone to chipping then the L67s just it's alot easier to throw too much pulley on a top swap then on a standard L67.

By the way KR doesn't chip pistons. KR is all timimg. Detonation chips pistons. Chipped pistons come when the PCM can no longer pull "retard" enough timimg to prevent detonation. All 0 KR gets you is the most usable power out of your motor.

thank you. just so that everyone knows, you cannot drop a pulley as easily on an L36 bottom end as easy as you can on a L67 bottom end. Can we all come to an agreement on that?


KR = retarded timing = detonation at a certain point = popped pistons

ok whats the most you can do with a top swaped L36 then, with all the proper supporting mods? that makes more sense i knew there had to be something more... lol thank you guys

what do you mean "whats the most you can do?"

what do you mean "whats the most you can do?"

i am going to be pretty far into the 12's. i am going to be very safe about it, and run 1.9's and then drop to a 3.4 or a 3.3. after that, i am going intercooler and dropping to a 3.0 or so. it should net me mid-low 12's

so you can make it to a 3.0 and it wouldnt blow your motor understably with supporting mods. what size pulley is that compared to the the L67 is it possibly to make a L36 a 10 sec car with the top swap?

Ok, with identical bottom ends, it can do just as much as an L67. All they're saying is you don't/can't use as much boost. A 3.0 on a top swap is like running a 2.6 on an L67. You have to be more cautious with pulley drops and scan with each one to make sure you have no KR.

ok thats great sorry for being a pain... lol you guys are soo helpful and im learning alot about these great cars ....

no problem. i did the same thing before