502 Exhaust !!

[1stoutlaw]

Finally buying some new parts to outfit a new 502----Have a chance to get a deal on the new and improved GIL exhaust---aluminum manifolds with the stainless elbows/tops....I thought for the money saved over stainless headers---I might be better off......ANY thoughts or comments from those who have used them ???

Thanks--Mike Tampa Bay !!!!

[Ratickle]

Depends on how much horsepower you hope to make. Runner length is important.

[C35]

was told once the orig gils had reversion probs due to short runners. is this improved?

didnt know gil was back- whos making them?

[Ratickle]

The Gils and Mercs really didn't have reversion issues. The issue was actually "drip down" (?) after the engines were shut off. They put those little anti-drip plates in and fixed that.

But, without longer, equal length, runners. I don't think any manifold does what it needs to for peak horsepower. So I think they are better than stock, but not much..... (Now I'm in trouble)

[1stoutlaw]

Thanks Guys------They have seperate runners through out the manifold and collect into one pipe/elbow----they are super light---water doesen't hit til the end of the pipe and I guess Hardin Marine bought them out----I guess a lil less HP from true headers but the HP gain will be fine for me-------------Thanks Mike--Tampa Bay !!!

[Ratickle]

Which model Hardins?

[C35]

looked at the site. only shows dry tails, gil used to have shorties- wet tails for using with cutouts etc. those reverted bad with bigger cams. unless hardin changed em they have short runners inside.

[Ratickle]

That's why I'm wondering which model number. I get news releases and flyers from Hardin. I'll check my last one. I think it was about exhaust....

[Ratickle]

You have to click on the wet exhaust to get their Gil replacement line-up.

[1stoutlaw]

Hardin wet exhaust 420-901018-sd

[C35]

look at this pic. theres only 3 runners. the center cyls are shared- that's why you get reversion



the wet tails mix water very close- just past the bend. dont take much at idle to pull water up and over that hump. they work just fine if you dont have much cam. crane 731 is abt max- thats not much hotter than the 502/465 stick.

the wets are nice for freeing up some ponies on a stock motor. if youre going for 550+ horse you need the drys. a deal isnt a deal if its not what you need.

[Ratickle]

Hardin wet exhaust 420-901018-sd

Thanks, we'll check it out real close...

[1stoutlaw]

----OK---C35 I looked at the photo but I never turned the manifolds over to look from that angle-----I know on the top they have 4 separate runners all going into 1 pipe/elbow/pipe??? SOooooo I don't know if mine are the same--yup mine, I already bought them on sale.....They also can be plumbed for closed/fresh cooling, which my new 502 has to be fresh/closed cooled... SSSooooo if I messed up to save a buck ??? I'm learning !!! Thanks for everyone's thoughts and comments !!!! Mike---Tampa Bay

[Ratickle]

----OK---C35 I looked at the photo but I never turned the manifolds over to look from that angle-----I know on the top they have 4 separate runners all going into 1 pipe/elbow/pipe??? SOooooo I don't know if mine are the same--yup mine, I already bought them on sale.....They also can be plumbed for closed/fresh cooling, which my new 502 has to be fresh/closed cooled... SSSooooo if I messed up to save a buck ??? I'm learning !!! Thanks for everyone's thoughts and comments !!!! Mike---Tampa Bay

I very much doubt you screwed up. My 420's ran the old Gils and worked just fine.
From Hardin's Website

Big Block Chevy Gil Replacement Bravo Wet Offshore System
420-901018-SD

Big Block Chevy Gil Replacement Bravo Wet Offshore System

Hardin Marine Offshore Wet Systems are designed for hi-performance and stock engines. This system mixes and discharges exhaust gasses with cooling water at the end of the exhaust pipe, and then a rubber hose connects up to your exhaust thru-hull ports. Custom pipes are also available for custom installations and are priced by measurements given. This same system is also used on Mercury hi-performance 525SC and HP500-engine packages as standard equipment from Mercury Hi-Performance.

Hardin Exhaust Systems perform better because they're made better, with great attention to detail in design, engineering and manufacturing. These manifolds are Hardincoated inside and out, proven to protect better than conventional marine coatings. These exhaust pipes are designed to keep cooling water separated from the exhaust flow to avoid corrosion of valves, rings and pistons. And these exclusive patented Turbulator Rings have proven themselves in protecting engines against water ingestion due to condensation.

Hardin Exhaust Systems are the overwhelming choice of boaters who want top-end performance with durability. These exhaust systems deliver by allowing your engine to breathe easier and perform better. Boaters spend thousands of dollars to modify their engines to increase horsepower and speed. But, unless the exhaust system is capable of the additional flow required, the modifications are wasted.

These exhaust systems allow center to center engine dimensions of 32-5/16" and are 1-5/8" taller than Mercury cast iron manifolds mounted on stock short decks with GM Heads.

[1stoutlaw]

Thanks Raticle---that is the system I bought and I feel better about them now !!!!!!

[MOBILEMERCMAN]

You should be happy with them.

Just make sure not to omit the turbulator plates { or believe anyone that states you don't need them or they restrict power}. They are there for a reason. Plan on flappers on the end of the pipe on the transom too.

[1stoutlaw]

OK-----What are "turbulator plates"---???--- I already have Rex Marine Tail pipes with metal flappers inside-----have had them for about 5 years !!!! Mike ---Tampa Bay !!!

[1stoutlaw]

OK---Mobilemercman-----I just looked up turbulator plates and YES my exhaust kit has them and Yes I will install them------Thanks so much--Mike---Tampa Bay !!!!