Thread: Top Swap Talk

Originally Posted by mofford12

By doing a top swap will this blow my motor?

Should headers be replaced ?

I live 5 minutes away from the JY, would it hurt to grab the parts off a junker gtp ssei or Riviera?

I don't really see a question here that hasn't been answered in the threads you speak of.
Yes, go to the junkyard. I love the junkyard, got a longblock L67 and 2004 CompG trans for $250 together.
Who wants to pay more for less? Pay less for more, as long as you can tell the junk aside from the spare parts.
The factory exhaust on the heads are manifolds, I would never M90 an L36/26 without headers/separate cylinder primaries.

The mileage on your car shouldn't be a huge factor if it is put together correctly and the pistons are completely intact as it sits.

Originally Posted by mofford12

So it's a must to replace the headers? Well i guess what I want to do is see how it went for the people who have done this..was it worth it...motor an tranny still running good

Replace the headers, no. You have OEM manifolds now I'm assuming, so you will want to purchase and install headers.

You can topswap any series II/ III naturally aspirated engine. Mileage, etc doesn't matter as long as the engine is good.

You will want to upgrade your tranny at some point. If you have no intention of going past a 3.8 pulley, then it shouldn't be too big of an issue.

What hp/torque gains does anyone estimate on a topswap???

Originally Posted by hockeybawler

I know that for horse power you gain about 5% more than what a stock gtp has. As far as torque I can not help you there

Really? Just so I'm understanding you, sir...5% more hp than a gtp even though im still naturally aspired? I'm not as educated when it comes to engine internal parts, but can take any info tossed at me. I would think i would still need a S/C to be equal> to a gtp after doing a topswap.

If this topswap is just as good as a supercharger, then I would much rather do the topswap vs supercharger or turbo too....at first.

high compression in the NA block, and low compression in the sc block.

this is why you dont want to run smaller then a stock pulley on the blower. stock is like a 3.4 on a top swap. due to the high comp.

GP GT's have a higher compression block, hence why its called an L36/26 as compared to a GTP L67 which has comparatively lower compression. hence more power from a supercharger on the GT (slightly better engine)


and a GP GT has a factory 3.29 final drive ratio in the Transmission, as compared to a GTP which has a factory gear of around 2.89.



thats why topswap cars are faster than factory supercharged ones.

*in a nutshell

Moffy...

You talk about wise guys in your thread, if you'd like...I could play that role for you. If not, why mention it? Silly
You say you read the top swap thread. It seems you might not fully understand that a top swap is swapping the heads, charger and intake manifold off of a SC motor onto an NA motor. Doing such a swap can net about 5% more than an origininally SC'd motor. The main difference is the compression ratio from the NA lower end.

Originally Posted by jerZcavy4120

GP GT's have a higher compression block, hence why its called an L36/26 as compared to a GTP L67 which has comparatively lower compression. hence more power from a supercharger on the GT (slightly better engine)


and a GP GT has a factory 3.29 final drive ratio in the Transmission, as compared to a GTP which has a factory gear of around 2.89.



thats why topswap cars are faster than factory supercharged ones.

*in a nutshell

I know this isnt much news to most of us on this forum or just mechanics in general, but this is what I like to here. I guess I should have known gtp's were low compression anyway. I already knew turbo/supercharger engines run a lot better with low compression...I just wasnt using my head this last night and this morning. Thanks guys.