Has anyone here tried the Hardin Marine typhoon headers?
I am running HP 500's that have been bumped up to 620 HP and was wondering if headers would make a noticable improvement over the Gil exhaust.
Jeff

They CMI E-tops should add 15-30 hp. If you are interested, I have two sets with tail pipes. E-mail me if you want to pursue.

I don't know anything about the Hardins.

But you may want to consider Stellings also

I have done extensive dyno testing with our "B" class engines we used to race the CMI E tops are worth every bit of 25-30 HP.

Etops will provide more power and of course that nice bling factor.

Fred is not kidding, there will be a 10% price increase.

Good luck with your project.

Kirk
Ateco Engine and Dyno Shop

Anybody ever do any comparisons with the "tube tops"? They look to have runners at least close to 32-34" in length and close to being equal length.

mrhorsepower1
Thanks for the response
These are 502's with the AFR 305's heads and a mild cam. All the parts are original HP500 except the heads and valve train and I like the stock look of the gil's.
The boat is a 382 Fastech, it responded well to the extra 100 hp per side with a 8 mph increase, I am not sure what 25-30 more would do.
Has anyone compared the E Tops vs sport tubes?

I have done back to back comparisons on the CMI E-tops vs. the Sport Tubes. The Sport Tubes make 15-20 HP more, but only above the 5200-5400 RPM range. There are points from 4000-5000 RPM where the E-tops make more torque than the SP's. The Sport Tubes start to shine from 5300-6800 RPM. On my combination, the 2 1/4" ID Big Tubes added another 20 HP over the SP's but again only at the higher RPM.
The E-Tops are the all around best value...except for the bling!

I had heard that there were ALOT of problems with the "Big Tubes" cracking around the mounting flange on the heads? Worth the extra 10-15 at that RPM?

I also noticed an increase of 30-40 hp from the Gils to the E-tops!

Dave

E Tops rock!