extending stock risers
#11
I wish I knew. It is problematic for SBC folk. The only thing I can tell you is that I've gone as far as a 221/230 @.050" on a 114 LSA roller cam and it doesn't revert with GLM manifolds and stock Merc stainless steel elbow/riser.
I'm not recommending you go dry either but the solution you seek with the stock manifold is elusive. I wish that weren't the case.
I'm just thinking out loud at this point but does anyone know if the Stainless Marine riser/elbows would bolt up? I don't think so but I haven't tried it.
I'm not recommending you go dry either but the solution you seek with the stock manifold is elusive. I wish that weren't the case.
I'm just thinking out loud at this point but does anyone know if the Stainless Marine riser/elbows would bolt up? I don't think so but I haven't tried it.
#13
Registered
The only thing I would add is if using it in saltwater you may want to go with stainless tube.
#14
Trash, I'm wanting to go to the Comp XM-276HR which is 224/230 @.050" but I think its a 110 LSA. But the 4 degrees less LSA combined with 3 degrees more duration means more overlap correct? EMI has some complete manifolds and risers that I can make work, I just don't want to spend that much to get the job done.
I will guess you are close to reversion. When I went to Crower and got my cam Jerry (at Crower) said don't go any bigger.
#15
We use these - Standard height thru transom stainless steel riser pipes fit stock Mercruiser center rise manifolds, as well as Glenwood Magnaflow manifolds. (Sold in pairs $1130.00) All kits include all necessary mounting hardware and gaskets. Weld on or Bolt on brackets available for Shift, ECM or EFI
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www.diamondperformanceparts.com
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The Best Parts & Service At The Best Price
#17
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iTrader: (8)
have stainless extensions welded on to your current exhaust portion of your risers. Tack weld extensions with the riser mounted in place to the current angle of your tips. Then pull the riser and fully weld. If done right the extension should not touch your exhaust hose. Bring the extensions to about 1 inch off of your current tips. Nothing else in your setup will have to change. I've done this with great success combating reversion.
I ran the xm276hr on a 355ci. With stock length risers it will revert water. Found small puddles in the center manifold runners. I added 8" extensions to my Hardin stainless risers to fix the problem. Was running GLM alum manifolds. Xm276hr is 224/230 on a 112+2.
I ran the xm276hr on a 355ci. With stock length risers it will revert water. Found small puddles in the center manifold runners. I added 8" extensions to my Hardin stainless risers to fix the problem. Was running GLM alum manifolds. Xm276hr is 224/230 on a 112+2.
#19
have stainless extensions welded on to your current exhaust portion of your risers. Tack weld extensions with the riser mounted in place to the current angle of your tips. Then pull the riser and fully weld. If done right the extension should not touch your exhaust hose. Bring the extensions to about 1 inch off of your current tips. Nothing else in your setup will have to change. I've done this with great success combating reversion.
I ran the xm276hr on a 355ci. With stock length risers it will revert water. Found small puddles in the center manifold runners. I added 8" extensions to my Hardin stainless risers to fix the problem. Was running GLM alum manifolds. Xm276hr is 224/230 on a 112+2.
I ran the xm276hr on a 355ci. With stock length risers it will revert water. Found small puddles in the center manifold runners. I added 8" extensions to my Hardin stainless risers to fix the problem. Was running GLM alum manifolds. Xm276hr is 224/230 on a 112+2.
Ryan, did you like that cam for a small block build? Did you run it straight up or advance it any? Mine will be a 383. Are those risers the Hardin 620-32410 part number that you started with? Thanks for the help.
#20
Registered
iTrader: (8)
I ran 1.6 rockers on intake with that cam for more lift/duration. Installed straight up as it has 2* advance ground in. With my AFR 190R heads it pulled very nice to 5600rpms. With it in a 383 it will be all in at 5000-5200 roughly. Mine were the 620-32420. If adding extensions these are what you want. The inner exhaust pipe is extended past the outer water jacket making it easier to weld too vs the 32410.