has anyone ever picked up mph/ rpm from switching from stock exhaust to emi thunder or any other manifold?looking at emi thunders for my 454 mag.was told by emi that i may see 2-300 rpm increase.thinking of sending my prop to get labbed but if i switch exhaust maybe i should wait.looking for real world test where only the exhaust was changed.

I'm about to replace my stock manifolds on my 454 Magnum too. Searching for a set of EMIs or CMIs at the moment. Let me know if you get to know any other info or recommendations as we're in the same boat. Thanks, Cliff. [email protected]

I would wait, Performance Manifolds should yield 2-300 rpm's. Let me know if I can help.

performance manifolds?are these in the process of being made?price?how long?

I put EMI Thunders on my 05 35' Fountain Ex. with 496s. It was enough to put me back on the rev. limiters. I was running 32p 5 blade maximus and had to send them back to Bblades for a little tweaking. In the end i picked up 3 mph in the mid-range and 2 on top end. Not alot for what it cost but the fuel consumption was less.

I agree about the cost and the payoff. However, the Merc manifolds will need to be relpaced at some time anyway (they are absolute junk). You may as well put some nice pieces on there. Save weight, add a little performace and add some bling too! And, a good exhaust system is crucial before adding any other performance mods anyway. I put EMI Thunders on my Formula and was very satisfied.

My .02

Definetly added to the bling I had the polished manifolds and Custom Cowlings polished covers for the water,ecm and the top cover plus the anodized cap covers. I'll get the disk out off of my old computer and find some pics. later this weekend.

I put the dana's on 454 mag in my 22 foot nordic sprint along with intake and carb got about 300 rpm. Based on the sales hype expected more but i think what i have is about what you could expect. it also looks and sounds faster

do you guys think there is any performance gain with the ss risers verses the alum risers besides the bling?who has the best price on emi thunders?

The biggest thing about the SS risers is they are longer and mix the water further away from the exhaust ports, thereby reducing your chances for reversion even more. But, they are a little pricy.