Mild SBC Upgrades
#21
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SB, I did a test fit with a Performer manifold (not vortec, but known height), trashed edelbrock 1409, and K&N flame arrestor. Clearances should be good for either Performer or RPM. BTW, edelbrock height specs are very close on both the Performer 2116 and RPM 7116. Only a 1/4" diff in average height, but perfomer has more of angle, front to back. Are you aware any highrise dual plane that takes a Q-jet? The performer being more of a mid-rise intake.
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Im with Travis, do the stroker otherwise you will be dissapointed with the results. Done right they can make some serious power even on regular fuel. You can yank that engine, get it apart and have it at the machine shop in half the time it would take to swap that cam. There is nothing wrong with a family boat with some grunt behind it.
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Dunno where you got the idle quality gripes with a Holley. As far as I am concerned, ANY carb with normal throttle plate shaft clearance can be tuned for good idle quality. Sloppy clearances (diameter OR side clearance) on the throttle plate shaft makes it hard for the plates to clost the same every time. Worn notch on the stop screw will do that, too. On any carb you want the plates ALMOST closed all the way, and tune with the idle bleed hole for best idle quality.
Q Jets are great for a rec carb.
Nothing wrong with a Holley spreadbore, or an Edelbrock.
Some of the Webers are more difficult to mess with with their capped passages and such.
Choose the MARINE carb of your choosing in the 600cfm range.
Performer intake is fine.
You haven't mentioned your cam choice or head mods.
I do think you are going to have a hard time getting 60 out of your setup as easily as you are thinking. Are your baseline speeds from GPS?
Good luck.
mc
Q Jets are great for a rec carb.
Nothing wrong with a Holley spreadbore, or an Edelbrock.
Some of the Webers are more difficult to mess with with their capped passages and such.
Choose the MARINE carb of your choosing in the 600cfm range.
Performer intake is fine.
You haven't mentioned your cam choice or head mods.
I do think you are going to have a hard time getting 60 out of your setup as easily as you are thinking. Are your baseline speeds from GPS?
Good luck.
mc
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Guys, I know you mean well, with the continued suggestions to go to a stroker. Please stop before I start to think too much about it, and start asking questions like "Who is good supplier of crate stroker motors?".
While I know I have 3-4 more good excuses why not to go to stoker, you may eventualy wear me down. And that does scare me! Because it won't stop there! It is probably a small step from stroker to big block, new drive, and before long a maxed out one.
For purposes of further discussions, lets assume a stroker is just not possible. Lets assume that I am locked in with a stock vortec head or a slightly modified one, and the stock mercruiser roller cam. The main choices left on the table are intake manifold and carb. I would also like to hear about the right gasket choices. When to choose GM or after market gaskets over the Merc.
Another area we haven't discussed is ignition and timing. I currently have Thunderbolt V with the V8-22A module. From reading past posts, this ignition curve works well with the vortec heads, which do not need as much advance. On the '96-'97 5.7L 2brls, the T5 does not have a knock sensor or knock module, or even a wiring harness that supports it. From examining the T5 system, the only other feedback is rpms. Does anyone know what the rev limiter is actually at? I know what the manual says, but have heard some conflicting field stories. If it is an issue, finding and converting to a T4 V8-22A module should be very easy.
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For purposes of further discussions, lets assume a stroker is just not possible. Lets assume that I am locked in with a stock vortec head or a slightly modified one, and the stock mercruiser roller cam. The main choices left on the table are intake manifold and carb. I would also like to hear about the right gasket choices. When to choose GM or after market gaskets over the Merc.
Another area we haven't discussed is ignition and timing. I currently have Thunderbolt V with the V8-22A module. From reading past posts, this ignition curve works well with the vortec heads, which do not need as much advance. On the '96-'97 5.7L 2brls, the T5 does not have a knock sensor or knock module, or even a wiring harness that supports it. From examining the T5 system, the only other feedback is rpms. Does anyone know what the rev limiter is actually at? I know what the manual says, but have heard some conflicting field stories. If it is an issue, finding and converting to a T4 V8-22A module should be very easy.
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A Performet intake will accomodate either a Q jet, or a Holley squarebore. I know this because I've been running around trying to find parts for the Holley. I bought the Performer with a Q jet on it, and I was thinking today that I better check that the Holley will work also. First thing I did when I got home was try both carbs on the intake, and made sure the butterflys will open. They do.
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[QUOTE=John_S]
For purposes of further discussions, lets assume a stroker is just not possible. Lets assume that I am locked in with a stock vortec head or a slightly modified one, and the stock mercruiser roller cam.
QUOTE]
I know you are keeping it simple but I would still recommend a cam change,the stock cam is not all that great and a better matched cam will get you closer to your goal,remember,the cam you have is for smaller heads,bigger heads will work better with a better cam,just do not go crazy,to make good power numberrs it is all about matching parts,like I said, a custom ground cam for your combo would work best and cams are not expensive for the poer gain.
For purposes of further discussions, lets assume a stroker is just not possible. Lets assume that I am locked in with a stock vortec head or a slightly modified one, and the stock mercruiser roller cam.
QUOTE]
I know you are keeping it simple but I would still recommend a cam change,the stock cam is not all that great and a better matched cam will get you closer to your goal,remember,the cam you have is for smaller heads,bigger heads will work better with a better cam,just do not go crazy,to make good power numberrs it is all about matching parts,like I said, a custom ground cam for your combo would work best and cams are not expensive for the poer gain.
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Here is my notes on the Merc SBC roller. Check part# on yours to see if same part # as below:
Stock hydr roller
GM#14097395/ Merc#431-811658
.004" 258, 272
.006" 249, 264
.050" 197, 207
.430", .450
109 LSA
Stock hydr roller
GM#14097395/ Merc#431-811658
.004" 258, 272
.006" 249, 264
.050" 197, 207
.430", .450
109 LSA
#28
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Cuda - you just need the $9 gasket sealing plate from Edelbrock or Holley to seal that Holley or other squarebore carb to the Performer's carb pad.
I believe Edelbrocks is part# 2732. I've even seen them at Autozone and Pep Boys and VIP and such.
http://www.edelbrock.com/automotive_..._spacers.shtml
It says 1.16" thick. This is typo. It's prob 1/16" thick since a thin steel plate. The pic is correct.
I believe Edelbrocks is part# 2732. I've even seen them at Autozone and Pep Boys and VIP and such.
http://www.edelbrock.com/automotive_..._spacers.shtml
It says 1.16" thick. This is typo. It's prob 1/16" thick since a thin steel plate. The pic is correct.
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SB: Those look like the specs I've seen in Dennis's book. I wasn't aware that there was a gm #, though. The cam will probably not arrive at my house for a couple of weeks, to confirm numbers. It is the Merc stock roller though.
Is there a mild cam suggestion that will work within the constraints of stock Vortec heads? Some of the ones in Dennis's book, I was not able to find at Jegs and other sources. I bellieve his cam suggestions were more for the non-vortec heads, too.
After more thought last night, I am pretty much decided on Edelbrock Performer 2116 and an electric choke marine Q-jet rebuild.
Is there a mild cam suggestion that will work within the constraints of stock Vortec heads? Some of the ones in Dennis's book, I was not able to find at Jegs and other sources. I bellieve his cam suggestions were more for the non-vortec heads, too.
After more thought last night, I am pretty much decided on Edelbrock Performer 2116 and an electric choke marine Q-jet rebuild.
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That intake will be fine.
I believe it is the Comp Cams fuel injection CARB EO type rollers that will fit. Basically need to keep them under .480 lift, bettery yet .460 lift or below just in case.
Yes, I believe the specs are from Dennis Moore's book. I looked it up in GM's catalogs and found their part #. Keeping this stuff in your notes can be very handy. No one can remember everything they run across as the years go on.
I believe it is the Comp Cams fuel injection CARB EO type rollers that will fit. Basically need to keep them under .480 lift, bettery yet .460 lift or below just in case.
Yes, I believe the specs are from Dennis Moore's book. I looked it up in GM's catalogs and found their part #. Keeping this stuff in your notes can be very handy. No one can remember everything they run across as the years go on.
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