Headers ?
 

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

Re: Headers ?
 

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.

Re: Headers ?
 

I don't know anything about the Hardins.

But you may want to consider Stellings also

Re: Headers ?
 

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.

Re: Headers ?
 

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

Re: Headers ?
 

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.

Re: Headers ?
 

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?

Re: Headers ?
 

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!

Re: Headers ?
 

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

Re: Headers ?
 

E Tops rock!

Re: Headers ?
 

Are the 2 1/8" dia primary of the stellings gray headers too much for a 620 hp 502 ? I believe the cmi sport tubes are 1 7/8".
Jeff

Re: Headers ?
 

Wags - I believe we have a mutual friend, who may suggest that 2 1/8 ID primary is too big.

I'm doing a build similar to yours, and I'll be bolting on KE's, with 1 7/8 ID runners. I was told that the 1 7/8 KE's will do quite nicely :D

Re: Headers ?
 

What is the difference between the regular sport tubes and the sport tubes that come on the 525EFI'S? I have been looking at upgrading for a long time. I have about 650 hp 540 afr 315 and a 1000cfm 4150 carb. could i expect about 80 hp over the gills?

Re: Headers ?
 

The Sport Tubes that come with the 525 efi:

1. has a different flange for the Edelbrock head. It won't fit a standard BBC head. Nor will a standard header fit the 525.

2. The collector to tailpipe flange is different. It's a Mercury flange.

3. The header length is different on the Merc version allowing equal length tailpipes on both sides.

4. The Merc 525 version has welded stainless steel distribution tubes.

5. Price. The Merc 525 version is only available through Mercury and is expensive to replace.

There may be additional differences.......

Re: Headers ?
 

I have a pair of lightening headers if you prefer. They have been run about 8 hours total time, and are powder coated red.

Re: Headers ?
 

send me some pics [email protected]

Re: Headers ?
 

Still time for a great deal on Etops as we have several sets in stock with stock tails. Let us know if we can help or provide pricing.

Kirk
Ateco Engine and Dyno Shop - YOUR CMI SOURCE in the Midwest, South and East Coast!! :D

Re: Headers ?
 

how much are e-tops? do you lose your silent choice with them (going from gils)?

Re: Headers ?
 

i would stay away from anything but stainless marine and stelling.....Just my opinon but i have had bad luck with cmi......i run a stainless marine gen iii on my 572 and it fixed a lot of problems i had ie water, dont risk it engines are too exspensive,,,,,,believe me i put 4 in my mag last season two of which were water related problems

Re: Headers ?
 

Sorry to hear that Nocig. Was it a reversion issue or other? Nobody makes a product with the intent of it not performing properly.

I don't know about staying away...Merc installs them on every one of their performance engines, Illmor installs them on all of their engines and just about every race boat uses them. Must be something about them. :D

Re: Headers ?
 

yes water, i am not knocking them i just like the security of a solid casting piece a little thicker metal and the guarentee.....once bitten twice shy ya know

Im very interested,price,engine size apli

Sorry, they were sold years ago...

i have stainless marine on mine for 20years i love them and i have a 540dart block dart pro 1 heads dart intake 1000holley carb msd 650hp . my buddy has stainless marine with 800hp:drink::drink: if money is no problem then go for what you want??