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View Full Version : Thru tansom exhaust/volvo penta



jstwkd
09-08-2002, 02:42 PM
Is thier some reason why I cant do a thru transom exh. system on 225 crownline with a volvo penta.I have the 5.7 GXI-DP SBC with thottle body inj. HP rating online says 320 is this correct.The sales person told me 280.Any help would be appreciated. Thanks

Dennis Moore
09-08-2002, 05:49 PM
There shouldn't be any reason why you can't go with a "through the transom exhaust" but you will be unhappy if you are looking for any performance improvements on a small block Chevy. Be sure that you use tips with flappers AND external salsbury type flappers (use both).
Sincerely
Dennis Moore

jstwkd
09-09-2002, 05:50 AM
Will this help performance at all.I was planning on changing exhaust manifolds.They want 1700.00 for the side exit exhaust.I rather spend the money on a better manifold.

Dennis Moore
09-09-2002, 02:56 PM
I don't know what exhaust manifolds you have (Mercruiser or Volvo) but I have installed all types of different high performance manifolds on Big Block Chevy marine engines and it always makes a big difference but very seldom have I been impressed with installing high performance manifolds on small blocks. The small block doesn't have the exhaust volume of a big block and the performance increase is less.
Check out the GLM small block exhaust manifolds. They are very reasonably priced, are a direct bolt on and increase performance as well as anything else.
GLM is in Monrovia, California 626-357-0077, they are the manufacturers but will tell you where you can buy them.

SchellSchock
09-09-2002, 03:05 PM
I'm interested in the same mods, more for the sound though. Thanks for the info Dennis.

gnarley
09-09-2002, 03:41 PM
jstwkd & SchellSchock, If you want the nice sound & a little power on your small block I'll say good luck but DON'T go with the side exhausts. They don't sound quite right, kind of listening to a 4 banger on each side I think the merging of the two exhausts near each other helps each one compliment each other hence the nice sound you get! And you may want to install a switchable exhaust so at times you can hear it & other times its quiet. I call it the Bitch switch & let you figure out the rest.
[ September 09, 2002, 04:41 PM: Message edited by: gnarley ]

SchellSchock
09-10-2002, 08:44 AM
Makes me wish I could put a crossover tube on exhaust like my cars, (Suburban and Vette both with Small Blocks). Seems to mellow exhaust note while still sounding Baaaaad!

Dennis Moore
09-11-2002, 07:01 PM
If you have a Mercruiser with "through the prop exhaust" you do have a cross over tube. It connects the exhaust manifolds before it enters the transom.
Dennis

SchellSchock
09-12-2002, 10:36 AM
I'm running a 2000 Volvo 5.7GSi,DuoProp, F8's will ThruTransom help any?????

RBook
09-25-2002, 07:02 PM
Hey jstwkd,
Have you tried the Crownline website? I bet you could find all your answers their. I have seen Crownlines with the side and hull exhaust and I agree the thru hull sounds better. I just saw a new Crownline two weeks ago on the lake, it looked around 23' and had thru hull exhaust and sound great.

jstwkd
09-30-2002, 06:30 AM
RBook, I did find the web sight.And a vovlo with thru transum.Exactly were I thought it would have to go thru.Planning on doing it this winter.
Unless I pick up another BBC for my jet.Then The 502 will go in the crown line.
Thanks