So im upgrading my 454 330 to the 502 hp500. I have the stock exhaust for the 454 will that exhaust work on the 502 without reversion or any other problems? I know I may loose some horsepower because of the flow of these but I will get exhaust during this winter?

Wow no one knows!!!

you will definetly have a problem with the 500hp cam and stock exhaust i am sure some one with more experience will chime in on this i think you are going to need some aftermarket exhaust even the exhaust that came on the 500s gill i think had reversion problems

get gill exhaust im running 500hps with 741 crane cams no problem with gills im making close to 600 hp. Stock 454 exhaust no way.

Problem is, the stock HP500 cam. 110lsa will want to revert. Get some gils with long risers/tails or something comparable, with long tails.

I am running Stainless Marine with 4 inches of rise and 18 inch tails and with a misfire the HP500 EFI will revert at idle. No way stock exhaust will not revert.

Ihave a buddy has 2 sets of gill manifolds in great condition he installed headers so has no need for them, He does not have the tails though. Make sure as said above use the long risers like i use.

Ok thanks for everyones input. What will reversion do? I heard of it but don't understand what can happen or what does happen.

How much would he want for the manifolds? would need just one pair and also need to know what type of risers to use with them

You will revert, I did w/ a HP500-similar cam and stock exhaust. Having milky oil in your system will break down crank/cam bearings along a host of other issues. It is essential, speaking from experience, to keep water out of your oil or you will have an additional anchor to use. If you do get water in it, you will want to change your oil as soon as you can or at the least fog your cylinders. Someone(MT?) on here told me to use Marvel mystery oil, that stuff is great!

Try to get the manifolds soon! I have some long Gil risers that I am trying to sell that might fit for your application. They do not fit my boat with the standard Bravo setup though.

I have the same risers (HP500) as the pic above and I still have a little water in two of the runners when I take the riser off, luckily when I start up it spits it out. I'm assuming this means I'm still suckin' some in and that is @ 114*lsa.

So just wanted to update everyone. I have the motor running and checked the exhaust for water and NO water with stock 454-502 exhuast. I am not having any reversion issues with the stock exhaust. Just wanted to let you all know that stock exhaust will work with a hp500 motor. The oil still looks brand new after Idling tuning and running for about 3 hours this weekend that is with no wake zones and tooling around to find a anchor point in a cove and about an hour of idle time while tuning