logs vs. headers

[andrew88]

this might be a dumb question...but on a small block, would i notice a good amount of power gain...if i went from exhaust logs to headers?? thanks.

[Flatmvn]

I don't think you would notice the difference, You would definatly notice the noise though. I had a friend that went from headers to Logs he lost about 300rpm. So in you case I think it wou be about a 300 rpm increase. As for the amount of power you would gain compaired to the water in your boat the higher chance of getting burned on the headers and the noise increase. I don't se you gaining anything. Just my .02

[andrew88]

alright thankyou very much!!...some drunk guy at the lake was going on about how its a night and day difference and all that...just making sure cuz i have back seats facing the motor too...wouldnt be a good idea to put headers on if it doesnt do too much :)

[AquaCraft]

Member Donald Duck E31 on this board runs a hot Z-28 350 in his hi-perf v-drive. I have driven the boat with headers and with the wet Edelbrock manifolds and it turns 7,000 RPM either way. The headers look and sound cool but for this SBC boat they make no noticable difference in performance.

[scot74]

I have also been curious to the log vs. header issue. I read and understand from every bodies experience there is not much difference as far as power output and rpm's, but has anybody done any actual dyno testing with both log manifolds and headers? Is it possible to run log manifolds with water running through them on the dyno? Last question - Do you fatten up or lean out your air-fuel mixture when converting from logs to headers? :rolleyes:

[hm66Howard]

Heck, I went from 180 degree headers to logs to make the boat safer for the kids and to install a ski-tow for them. Since it's a junkyard engine in there right now, I can't give you any performance difference. Feels the same to me and, no loss of RPM. The wife likes the way it sounds now too. A sound she is more familiar with!

[RiverRacer]

Heck, I went from 180 degree headers to logs to make the boat safer for the kids and to install a ski-tow for them. Since it's a junkyard engine in there right now, I can't give you any performance difference. Feels the same to me and, no loss of RPM. The wife likes the way it sounds now too. A sound she is more familiar with!

I made the switch in my ski boat and there was no difference, only time you'd see a difference if any, would be at WOT!.. I've seen blown boats run well over a 100 with logs!. Some do flow better than others though!..

[RiverRacer]

Is it possible to run log manifolds with water running through them on the dyno?
You can but plumbing might be an issue if they're not setup for it!..

Do you fatten up or lean out your air-fuel mixture when converting from logs to headers? :rolleyes:
You run it and read the plugs!..

[Camp10]

I made the switch in my ski boat and there was no difference, only time you'd see a difference if any, would be at WOT!.. I've seen blown boats run well over a 100 with logs!. Some do flow better than others though!..

I am considering changing from headers to going through the transom with logs on my sanger. Which logs flow the best for a BBC? Right now I have a worked over 468, but considering a mild blower motor for next summer.

[RiverRacer]

I am considering changing from headers to going through the transom with logs on my sanger. Which logs flow the best for a BBC? Right now I have a worked over 468, but considering a mild blower motor for next summer.

Any one that has smooth flowing ports are best, Glenwoods are one of them!..

[andrew88]

what about the sbc edelbrock ones?

[RiverRacer]

Don't know, are they like the Glenwoods with blended runners?, if it's just a ski boat it don't much matter anyhow!..