Raylar

Installers of exhaust manifolds on BBC blocks and heads should also be careful to check the needed clearance between the heads of the head bolts (bolts) or nuts on head studs(studs) on the bottom row of head bolts under the manifolds as a lot of cast manifolds and even some header flanges can and will hit when the manifold or header is bolted in place and not allow the bottom of the manifold to pull in tight and seal on the gasket. Just another thing to check on assembly.

Best Regards,
Ray @ raylar

Randy Nielsen

iTrader: (4)

My thoughts exactly Ray, I put head studs on one of my 502s & found I had to grind the top of the stud or pocket the EMI Thunder exhaust manifolds I was using. I pocketed the manifolds on all 8 lower studs. Fortunately their was enough material to do this.

pitts1313

Think this is what happened. I only had about an 1/8th inch gasket coverage in areas. Cleaned everything up and reinstalled with the stainless felpros on both engines paying attention to the head bolts, which don't interfere.There is big difference in the felpro material and the EMI gasket. I have EMI exuast tips and the rubber on the flappers is blown half way off on 3 out 4 tips with only about 25 hours. EMI offered to repair, may just let the exhaust clank. I think a little better quality material would go a long way.

AIRFOIL292

I found the gaskets do not match up correctly on the EMI manifolds. The bolt holes need to be lowered to have the ports line up. I lay them out on the manifold and use a rat tail file to elongate the hole. I then tack the gasket to the manifold before installing to head. EMI should make a gasket made tailored to this manifold....

Robertjr

The first mistake all of you made was buying 3rd rate manifolds. Friend of mine did the same thing and it ended up costing him big. Not sure about imco but those EMI brand exhaust are not any better than the old style merc manifolds that came on 502-454 magnums. I would be suspicious of anything that had water jackets relying upon a gasket to separate from the exhaust. Only type of manifolds that should ever get used are Stainless Marine brand, no water jackets where the manifold and pipe come together not to mention they are about the same price as EMI............................................... ........Rjr.....................................

ACrooks69

iTrader: (1)

The EMI manifolds are not like factory merc manifolds and the water does not pass through the riser flange. They have not had that style in at least 10 years. My SBC manifolds are quite nice IMO.

FIXX

iTrader: (2)

how come you havnt changed your pic to a fountain yet?

FIXX

iTrader: (2)

P.S. your talking out your ass dude,,their not the same as merc manifolds..i am a dealer for emi and have installed over a hundred of them and have not had any issues and all the exhaust ports lined up fine with the heads..and yes the manifolds dont have any holes in them anymore like the merc's did...emi manifolds are also anodised and with stant the roughest water..if theirs any issues with the manifolds its always installer error or the persont used the wrong gaskets like this guy that started this trend..felpro dont make stainless manifold gaskets,,what he used were alunimum BBc car manifold gaskets which wont hold either..and as for the rubber flaps having to be burnt well that is because of lack of water or sucking up mud and packing the exhaust full so water can cool the tips..

Just my o2..

ps get your rubbers fixed you it will lead to another trend,,emi caused my engines to revert water and now my engines are seizes..

Robertjr

Perhaps I don't recall all the details regarding my friends boat that screwed up HOTSHOT! but I definitely remember that they were very restrictive at best! I would not give them away let alone sell them! Furthermore I'm not going to get in a key board match about equipment that is Junk!!!! Stainless Marine brand is the best Manifold style exhaust bar none!.......................................Rjr... .................... just my two cents

Expensive Date

On my list of things to do.