Can anyone tell me why these two engines appear identicle but are rated differently and also have different power graphs? Please no wild *** guesses, only confirmable facts as we're trying to put together a new endurance racing class for a marine application.

GMPP does not offer any dealer support up here in Canada!! This is what burns me most about GM trying to be big in the performance market, is that there is no technical support, you can't talk directly to anyone technical. There's no problem talking directly to an engineer at Dart, Brodix, Edelbrock, All Pro, Jesel, T&D, Manley, but at GMPP a person has to try and relay all your technical questions through a partsman at your local GM dealership that doesen't have the technical training to help, they're parts people not engineers. Can you imagine how long any of the above listed businesses would stay in business if they wouldn't offer any technical assistance directly to engine builders and tuners, just to the local hot rod parts shops that sold their products and 97% of the sales people at these local hot rod part shops also don't have the technical expertise.............this is why the above aftermarket companies have engineers you can talk directly to. GMPP has no contact info on their website, all the other aftermarket companies do!!

The only differences I've been able to determine are that the CT525 has;

- circle track oil pan
- SFI Balancer
- water pump is designed with restrictors and no thermostat
- it is a sealed engine.
- ***the intake manifolds appear to be different in the 2009 GMPP Catalogue, look at the height of the plenum, the angle of the runners at the head and how the two front runners match up?

Are any of the internal parts for the CT525 engine different because it's designed specificallly for racing?

 

Sorry about the lack of support above the border. I don't have a clue how that works.

I would say that you are correct about the engines.

I will find out why the difference in power.

Thanks

Robin

 

Hey Riveracer,

I am an engineer at Roush that did the engine durability testing and power verification for GMPP on both the CT525 and 376/515. You are correct - with the exception of pan and balancer, they are the same engine. THe reason for the difference in power levels is the type of carburator used for power verification. The CT525 used a Holley 750 HP for racing apps, while the 376/515 used a Holley 770 for a street friendlier setup...

 

Wow! Now there's an answer for ya!!!

 

West1NM - Thank you for your reply. I would like to speak with you personally if possible to discuss some technical questions I have about this engine (cooling and oiling system, weak links, intake manifold, etc), you can PM me with your contact info if you like. Thanks in advance!