392 Stroker Crate Engine Output?

[Fred Douglass]

Hey Blykins, Sir---

Fill me in on the heinous losses suffered via side-pipes. Like your average ingnoramus, I assumed they were far freer-flowing than under-body pipes with mufflers, etc. Is this loss to be expected with pretty large sidepipes with those spiral "muffler" inserts? Kinda discouraging. What's the best solution? I just don't know about stripping the spirals out---not in Massachusetts, anyway, with the Red Guard out, sniffing for decibelage.

[blykins]

Hey Freddy,

I think it's due to the restrictive size of the muffler inserts on the pipes. I think most pipes are like 4" OD, but sometimes you couldn't squeeze a golf ball through the muffler insert. I think it was Red Barchetta who did a sidepipe rebuild and showed the difference between the muffler ID sizes on his SPF.

I have also rebuilt my sidepipes. Actually I didn't rebuild them, I sold them and built a set myself. The glass pack inserts are unbelievably tight...I bet the ID on my set was around 2".....that's not enough for a 400-500 hp engine. On my new set, I ditched the sidepipes altogether and used Howe Racing mufflers. I can get away with that in my neck of the woods....don't think it would be a likely option for most though.

Another theory I have is the placement of the collector on the header. Essentially the headers don't have collectors. It's the sidepipes that have the collectors....and sometimes I wonder if it's too far away from the heads to really scavenge the exhaust out.

Do a search for Lobak mufflers.....I think some members have had some good results from those......increased flow without an increase in noise.