Sbc 350 GLM exhaust Porting
05-08-2018, 11:27 AM
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Sbc 350 GLM exhaust Porting
I was thinking about buying a pair of GLM exhaust manifolds and porting them out to match my AFR heads I know you guys are gonna think I’m crazy But the manifolds aren’t that expensive a lot cheaper than aftermarket and I figure if I can open them up should work just as good right ? Die Grandor Some Bose noise canceling headphones And a beer and have at it what do you guys think. open up the ports to a 1 3/4 or 1 5/8 you know if thes room
05-08-2018, 11:14 PM
#4
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I hear you AFR heads plus a cam and then cancelling that all out with a close matched poor flowing OEM exhaust manifold and riser.
Actually you are going backwards ---- did you know your cork in the system is the stock exhaust riser as well. Its the same riser and gasket a 175 hp thru 190 hp V-6 mercruiser uses. Wanted to pass that info on
Actually you are going backwards ---- did you know your cork in the system is the stock exhaust riser as well. Its the same riser and gasket a 175 hp thru 190 hp V-6 mercruiser uses. Wanted to pass that info on
Last edited by BUP; 05-08-2018 at 11:33 PM.
05-09-2018, 09:38 AM
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I ran unported GLM aluminum manifolds on my old 383 SBC. Risers were Imco 4" dry to transom. This setup supported 475hp and 80.5 gps speeds. Sure a set of CMI's would probably outperform the above setup. Don't waste your time porting the GLM's. The restriction is on the riser as stated above.
05-09-2018, 11:49 AM
#8
I ran unported GLM aluminum manifolds on my old 383 SBC. Risers were Imco 4" dry to transom. This setup supported 475hp and 80.5 gps speeds. Sure a set of CMI's would probably outperform the above setup. Don't waste your time porting the GLM's. The restriction is on the riser as stated above.
05-10-2018, 10:30 PM
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anything cast will always have room for improvement
looking at the cross section there looks to be a little bit of room to open up in the ports. but with that said your mileage may vary
I don't know what cam you're running, but if its it is a stock cam i would port these a little. at least clean it up, port transition, casting flash, radius, smoothing things out. If you start removing lots of material I would be a little more cautious.
looking at the cross section there looks to be a little bit of room to open up in the ports. but with that said your mileage may vary
I don't know what cam you're running, but if its it is a stock cam i would port these a little. at least clean it up, port transition, casting flash, radius, smoothing things out. If you start removing lots of material I would be a little more cautious.
