Hood clearance
Thread Starter
Intermediate
Joined: Apr 2006
Posts: 28
Likes: 0
From: Milwaukee WI
Hood clearance
I'm currently changing my 1971 original 350cid engine for a 383cid engine.... as you have read in the previous posts I just wrote...
I know that different years of C3's had different hood heights, so I can't speak for all years (I've read that the early C3's were the lowest...)
To all that are insterested in hood clearance for a 1971, the key is a drop base air filter. My set up is a Proform carb with the vent tubes cut to 1/2" (PRO-67205), RPM Air Gap (milled down approx 3/16"), L88 drop base air filter(part #152088), 3" air filter.
When I close the hood i have 5/8" clearance from wing nut to bottom of hood. I guess that I didn't need to mill the intake.
Thanks to the forum I got to keep my stock hood.
Best Regards,
Rod
PS: to assure that the carb had enough air flow I put the K&N X-stream(KNN-66-1401XP) air filter top on.
I know that different years of C3's had different hood heights, so I can't speak for all years (I've read that the early C3's were the lowest...)
To all that are insterested in hood clearance for a 1971, the key is a drop base air filter. My set up is a Proform carb with the vent tubes cut to 1/2" (PRO-67205), RPM Air Gap (milled down approx 3/16"), L88 drop base air filter(part #152088), 3" air filter.
When I close the hood i have 5/8" clearance from wing nut to bottom of hood. I guess that I didn't need to mill the intake.
Thanks to the forum I got to keep my stock hood.
Best Regards,
Rod
PS: to assure that the carb had enough air flow I put the K&N X-stream(KNN-66-1401XP) air filter top on.
Le Mans Master
Joined: Apr 2007
Posts: 7,353
Likes: 72
From: Graceland in a Not Correctly Restored Stingray
You probably know this, but I didn't want to leave it left to assumption... Be sure to match your ports. It's something that ought to be done anyway, but especially after milling the intake. You absolutely don't want to leave any possible abrupt step down (large to small) into the head unattended to, even if it does mean a little epoxy work.
Glad you're happy about the hood, and hope everything else works out just fine, too.
Glad you're happy about the hood, and hope everything else works out just fine, too.
Race Director
Joined: Feb 1999
Posts: 19,659
Likes: 34
From: Lenoir City Tennessee
Ci 6, 8 & 10 Veteran
St. Jude Donor '05-'06-'07-'08-'09-'10-'11-'12-'13-'14-'15
I am using the RPM Airgap with a drop base on mine and have about 1/4 inch clearance on an LT-1 hood.
Burning Brakes
Joined: Dec 2003
Posts: 1,004
Likes: 7
From: Adelaide South Australia
I'm currently changing my 1971 original 350cid engine for a 383cid engine.... as you have read in the previous posts I just wrote...
I know that different years of C3's had different hood heights, so I can't speak for all years (I've read that the early C3's were the lowest...)
To all that are insterested in hood clearance for a 1971, the key is a drop base air filter. My set up is a Proform carb with the vent tubes cut to 1/2" (PRO-67205), RPM Air Gap (milled down approx 3/16"), L88 drop base air filter(part #152088), 3" air filter.
When I close the hood i have 5/8" clearance from wing nut to bottom of hood. I guess that I didn't need to mill the intake.
Thanks to the forum I got to keep my stock hood.
Best Regards,
Rod
PS: to assure that the carb had enough air flow I put the K&N X-stream(KNN-66-1401XP) air filter top on.
I know that different years of C3's had different hood heights, so I can't speak for all years (I've read that the early C3's were the lowest...)
To all that are insterested in hood clearance for a 1971, the key is a drop base air filter. My set up is a Proform carb with the vent tubes cut to 1/2" (PRO-67205), RPM Air Gap (milled down approx 3/16"), L88 drop base air filter(part #152088), 3" air filter.
When I close the hood i have 5/8" clearance from wing nut to bottom of hood. I guess that I didn't need to mill the intake.
Thanks to the forum I got to keep my stock hood.
Best Regards,
Rod
PS: to assure that the carb had enough air flow I put the K&N X-stream(KNN-66-1401XP) air filter top on.
This is very interesting.... You're the first to state an rpm airgap actually fits under a stock chrome bumper small block C3 vette.
Would love to see a pic of your setup. Can you post one up?
.
.
My motor should be arriving (at long last) within a few weeks.
Delays with shipping to Australia have peeved me off a little.
Motor only took 4 weeks to build from placing order, but has taken 3 months to get to Oz...
I don't expect my stock bonnet to clear with my Vortec rpm airgap, but
you give me some hope that it may be possible with some mods...
I have been waiting to get the engine to take some actual measurements before deciding whether to get a new hood - LT1 or L88 style. These aren't cheap as an item, and get ridiculously expensive when factoring shipping costs.
Eddie... what size air cleaner (height) are you using under that LT1 hood. Is it 3" or is it smaller ( 1.5" )
I prefer the look of the LT1 hood, but I do like the fact that the L88 hood allows for full sized (height) air filter AND unrestricted cool air to be drawn in. Should add a couple of more horses too .....
cheers
tom
Thread Starter
Intermediate
Joined: Apr 2006
Posts: 28
Likes: 0
From: Milwaukee WI
You probably know this, but I didn't want to leave it left to assumption... Be sure to match your ports. It's something that ought to be done anyway, but especially after milling the intake. You absolutely don't want to leave any possible abrupt step down (large to small) into the head unattended to, even if it does mean a little epoxy work.
Glad you're happy about the hood, and hope everything else works out just fine, too.
Glad you're happy about the hood, and hope everything else works out just fine, too.
BR,
Rod
Thread Starter
Intermediate
Joined: Apr 2006
Posts: 28
Likes: 0
From: Milwaukee WI
Thread Starter
Intermediate
Joined: Apr 2006
Posts: 28
Likes: 0
From: Milwaukee WI
Rod.....
This is very interesting.... You're the first to state an rpm airgap actually fits under a stock chrome bumper small block C3 vette.
Would love to see a pic of your setup. Can you post one up?
.
.
My motor should be arriving (at long last) within a few weeks.
Delays with shipping to Australia have peeved me off a little.
Motor only took 4 weeks to build from placing order, but has taken 3 months to get to Oz...
I don't expect my stock bonnet to clear with my Vortec rpm airgap, but
you give me some hope that it may be possible with some mods...
I have been waiting to get the engine to take some actual measurements before deciding whether to get a new hood - LT1 or L88 style. These aren't cheap as an item, and get ridiculously expensive when factoring shipping costs.
Eddie... what size air cleaner (height) are you using under that LT1 hood. Is it 3" or is it smaller ( 1.5" )
I prefer the look of the LT1 hood, but I do like the fact that the L88 hood allows for full sized (height) air filter AND unrestricted cool air to be drawn in. Should add a couple of more horses too .....
cheers
tom
This is very interesting.... You're the first to state an rpm airgap actually fits under a stock chrome bumper small block C3 vette.
Would love to see a pic of your setup. Can you post one up?
.
.
My motor should be arriving (at long last) within a few weeks.
Delays with shipping to Australia have peeved me off a little.
Motor only took 4 weeks to build from placing order, but has taken 3 months to get to Oz...
I don't expect my stock bonnet to clear with my Vortec rpm airgap, but
you give me some hope that it may be possible with some mods...
I have been waiting to get the engine to take some actual measurements before deciding whether to get a new hood - LT1 or L88 style. These aren't cheap as an item, and get ridiculously expensive when factoring shipping costs.
Eddie... what size air cleaner (height) are you using under that LT1 hood. Is it 3" or is it smaller ( 1.5" )
I prefer the look of the LT1 hood, but I do like the fact that the L88 hood allows for full sized (height) air filter AND unrestricted cool air to be drawn in. Should add a couple of more horses too .....
cheers
tom
I would like to take credit for being the first to make this combo work on CF but to many people would call
.... I learned how to do it from CF. I can email you some pics if you want?BR,
Rod
Racer
Joined: Oct 2006
Posts: 306
Likes: 1
From: Burnaby BC
RPM Air Gap (milled down approx 3/16"), L88 drop base air filter(part #152088), 3" air filter.
When I close the hood i have 5/8" clearance from wing nut to bottom of hood. I guess that I didn't need to mill the intake.
Thanks to the forum I got to keep my stock hood.
Best Regards,
Rod
PS: to assure that the carb had enough air flow I put the K&N X-stream(KNN-66-1401XP) air filter top on.
When I close the hood i have 5/8" clearance from wing nut to bottom of hood. I guess that I didn't need to mill the intake.
Thanks to the forum I got to keep my stock hood.
Best Regards,
Rod
PS: to assure that the carb had enough air flow I put the K&N X-stream(KNN-66-1401XP) air filter top on.
I have a 69 with stock 350 hood and I could only fit a Performer EPS.
My closest point is at the front passenger side air cleaner and I have 1/4 inch only.
My question is that in milling the air gap down how does it effect its performance?
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Le Mans Master
Joined: Apr 2007
Posts: 7,353
Likes: 72
From: Graceland in a Not Correctly Restored Stingray
OzzyTom, I don't believe he's got the entire cold air setup installed, rather only the base to get the filter down as low as possible, if I'm reading that right. The L88 setup has no way to work without the cowl induction hood...
Racer
Joined: Oct 2006
Posts: 306
Likes: 1
From: Burnaby BC
I just went to the local parts place and picked up the following for my 69 with stock 350 hood:
Polished Performer Air-Gap (non-EGR) #26011*
Manifold height: A-3.72", B-4.92" (.27" taller than #2101)
Polished RPM Air-Gap (non-EGR) #75011*
Manifold height: A-4.20", B-5.25" (same as #7101)
I got the 26011 to fit under my hood. This is odd since even Edelbrock says it will not fit.
The 75011 touches solid at the front passenger side.
Thanks for the post.
Now I think I have a polished Performer EPS for sale.
Polished Performer Air-Gap (non-EGR) #26011*
Manifold height: A-3.72", B-4.92" (.27" taller than #2101)
Polished RPM Air-Gap (non-EGR) #75011*
Manifold height: A-4.20", B-5.25" (same as #7101)
I got the 26011 to fit under my hood. This is odd since even Edelbrock says it will not fit.
The 75011 touches solid at the front passenger side.
Thanks for the post.
Now I think I have a polished Performer EPS for sale.
Burning Brakes
Joined: Dec 2003
Posts: 1,004
Likes: 7
From: Adelaide South Australia
Yes please... I'm keen to see pics.
So milling the top of the manifold is your secret.....
I don't suppose anyone has done any before/after dyno runs with this mod ???
.... I'd imagine the effect would be minimal, but then again, I'd be only guessing.
well done.
tom
Le Mans Master
Joined: May 2006
Posts: 9,993
Likes: 1,136
From: League City Tx
Interesting...Nice work...
BTW 632C2 was the first to mill the carb pad to get an RPM under a stock C2 SB hood.
My question is, if you are running the L88 air cleaner base, what are you using for the filter? Doesn't the filter normally stay up in the L88 hood cowl? are you just running the screened bottom and thats it?
Pics posted here would be greatly appreciated....
I know MANY members here want to get an Air Gap under a 68-72 SB hood.
BTW 632C2 was the first to mill the carb pad to get an RPM under a stock C2 SB hood.
My question is, if you are running the L88 air cleaner base, what are you using for the filter? Doesn't the filter normally stay up in the L88 hood cowl? are you just running the screened bottom and thats it?
Pics posted here would be greatly appreciated....
I know MANY members here want to get an Air Gap under a 68-72 SB hood.
Burning Brakes
Joined: Dec 2003
Posts: 1,004
Likes: 7
From: Adelaide South Australia
I can tell you all that the Edelbrock Vortec RPM Air Gap manifold fitted on my sbc with a drop base and a 1.5" air filter does actually fit under my stock small block hood.... just.
I have 1/2" thick hood insulation, and the air cleaner just makes contact with it.....The hood actually closes, but under torque, I'm sure there is a lot more movement which would be an issue.
The drop base and low height filter would also create an air flow reduction which would definitely impede upper rpm power, so It is NOT a good long term setup.
This is a temporary situation till my L88 scoop arrives next week, and I get it installed.
I have 1/2" thick hood insulation, and the air cleaner just makes contact with it.....The hood actually closes, but under torque, I'm sure there is a lot more movement which would be an issue.
The drop base and low height filter would also create an air flow reduction which would definitely impede upper rpm power, so It is NOT a good long term setup.
This is a temporary situation till my L88 scoop arrives next week, and I get it installed.
