SBC intakes Holley 300-25 vs 300-2

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1980RS
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Re: SBC intakes Holley 300-25 vs 300-2

Post by 1980RS »

GOSFAST wrote: Thu Aug 06, 2020 2:10 am Not sure tonight the difference in the two intakes but I can give you this much on the 300-25, back in the mid '80's we began welding in some "fins" and did a little porting and was able to pick up about 30 HP. We saw it on the dyno and some close customers who used it picked up 3-tenth's at the strip!

See the photo below, on this one the "fin" work is finished and ready for the porting!

Thanks, Gary in N.Y.

P.S. Back in those days the 350" was much more prevalent than the larger SB inch units, we never got to really test it much on the 400" platform but figure it would perform as well with the "fins" installed. We still do a couple during the year, but not as many as in the past!

SBC Strip Dom-Mod A.JPG
I know that mod does work on those intakes. I had a friend back in the late 80's did that to his BBC Holley intake and it picked up so much ET he about fell over at the track. The guy doing them was overwhelmed with work for a while when the word got out. I need to practice more welding before I try that trick. Nice work by the way.
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Re: SBC intakes Holley 300-25 vs 300-2

Post by dave brode »

Do you need a mini tig torch to get at the side that is outboard? Or will a flex head #17 work?
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Re: SBC intakes Holley 300-25 vs 300-2

Post by falcongeorge »

1980RS wrote: Thu Aug 06, 2020 9:21 am
GOSFAST wrote: Thu Aug 06, 2020 2:10 am Not sure tonight the difference in the two intakes but I can give you this much on the 300-25, back in the mid '80's we began welding in some "fins" and did a little porting and was able to pick up about 30 HP. We saw it on the dyno and some close customers who used it picked up 3-tenth's at the strip!

See the photo below, on this one the "fin" work is finished and ready for the porting!

Thanks, Gary in N.Y.

P.S. Back in those days the 350" was much more prevalent than the larger SB inch units, we never got to really test it much on the 400" platform but figure it would perform as well with the "fins" installed. We still do a couple during the year, but not as many as in the past!

SBC Strip Dom-Mod A.JPG
I know that mod does work on those intakes. I had a friend back in the late 80's did that to his BBC Holley intake and it picked up so much ET he about fell over at the track. The guy doing them was overwhelmed with work for a while when the word got out. I need to practice more welding before I try that trick. Nice work by the way.
1980RS, you were asking about my epoxy divider extensions on a Weiand 2575, I didn't extend them anywhere NEAR are far as the ones in the photos above, but the vertical shape of the leading edge in the photos is very similar to what I did. I could be totally out to lunch here, but it just feels wrong to extend the dividers that far into the plenum with a big bore spread like a Q-jet. I feel like you would be inviting fuel distribution problems, and I don't have a dyno to sort issues like that out.
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Re: SBC intakes Holley 300-25 vs 300-2

Post by dave brode »

snipped

Please describe the car and combo
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Car is an 80 Camaro s.
[/quote]

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Re: SBC intakes Holley 300-25 vs 300-2

Post by EDC »

GOSFAST wrote: Thu Aug 06, 2020 2:10 am Not sure tonight the difference in the two intakes but I can give you this much on the 300-25, back in the mid '80's we began welding in some "fins" and did a little porting and was able to pick up about 30 HP. We saw it on the dyno and some close customers who used it picked up 3-tenth's at the strip!

See the photo below, on this one the "fin" work is finished and ready for the porting!

Thanks, Gary in N.Y.

P.S. Back in those days the 350" was much more prevalent than the larger SB inch units, we never got to really test it much on the 400" platform but figure it would perform as well with the "fins" installed. We still do a couple during the year, but not as many as in the past!

SBC Strip Dom-Mod A.JPG
I remember back in the NHRA "Super Modified" days, a couple of friends have Al Neal intakes with those "fins" in the plenum.

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Re: SBC intakes Holley 300-25 vs 300-2

Post by bthomas »

How does the -2 compare to other lowered height single planes such as the Victor jr or team g?
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Re: SBC intakes Holley 300-25 vs 300-2

Post by Walter R. Malik »

bthomas wrote: Wed Aug 19, 2020 7:52 am How does the -2 compare to other lowered height single planes such as the Victor jr or team g?
There are 2 different versions of the Holley 300-2 intake manifold; original and revised.
The style is sorta like the old Offenhauser Port-O-Sonic.

How any intake manifold would perform depends greatly upon the engine under it.
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