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Discussion Starter #1
On a fairly mild 460 BBF are a set of Bassett thru transom headers going to make much of a difference in performance? Currently running Hardin Marine logs.

Thanks
 

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Angry American
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to answer your question, yes, they will make a difference. If you are going from logs/risers, there's a chance you could get an additional 300 rpm but there are many variables that come into play.
Carb, intake, cam, heads, valve size all play a part....even the type of log that's on the engine now.

My engine ended up with about 300 rpms more over the Hardin Marine logs with 2-7/8" risers but only about 100 over the Harmon logs and risers that were hogged out to about 3-1/4". Big block chevy though.
 

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Discussion Starter #3
Cool thats what I was wondering. FWIW D0ve heads, stock valves, roller rocker, just shy of 10-1 compression, flat tappet cam, tunnel ram with dual holley 450's.

Any midrange or are all gains going to be top end? And if it matters these are thru transom headers.
 

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Angry American
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yes, mine are thru transom and yes, I did get better throttle response over the Hardins. I don't remember if it was on here or on the old Hot Boat forums where I posted up the numbers each time I made a change. I'm thinking it was on HB and most of it was info in regards to carb and intake changes, some about the exhaust.
Since not every engine is the same, results will vary but also keep in mind that just because the engine gets more rpm, it doesn't necessarily mean the boat will pick up speed. That's a whole other area of discussion in regards to the hull itself.
 

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Cool thats what I was wondering. FWIW D0ve heads, stock valves, roller rocker, just shy of 10-1 compression, flat tappet cam, tunnel ram with dual holley 450's.

Any midrange or are all gains going to be top end? And if it matters these are thru transom headers.

Did you do any port work on the exhaust?
 

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Angry American
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No port work.


Cas thanks for your input. Much appreciated
I just did a little searching, are you thinking about putting them on the Hallett or did you sell it and putting them on a different boat?
If it's the Hallett, keep in mind Bassett TT's shouldn't be put under an engine cover, they get way too hot for that. Basically, you would need to lose the cover so you have an open engine. Also, that Hallett is a well built hull that's on the heavy side so you may not see real mph gains in the top end.
 

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Discussion Starter #9
They would be going on the Hallett. I was concerned about the engine cover. I was thinking I would use some header wrap. After what you guys are saying it sounds like maybe I should just stick with the stockers?

Thanks CP for your input as well.

I really thought since I would have less water flowing thru the exhaust that It would help out a lot.
 

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They would be going on the Hallett. I was concerned about the engine cover. I was thinking I would use some header wrap. After what you guys are saying it sounds like maybe I should just stick with the stockers?

Thanks CP for your input as well.

I really thought since I would have less water flowing thru the exhaust that It would help out a lot.
go center risers...



 
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