SBC How Much HP with FP 90314 ?

[Tom68]

How much Horsepower can we get through a Felpro 90314 on a 350 ?
Lets call the port size as 2" x 1.25", Felpro lists it a little smaller.
How much HP can we make NA as a race motor ? and how much as a streetable NA motor ?

Back when all we had was Fuelie heads that was your reliable gasket grabbing port dimension, Grumpy and Co would have pushed it far beyond that of course.

I guess we could also accept raised port options with the same port face dimension, since we could use spacers along with a milled down distributor mount to get there.

Lets call it a how much horsepower with a 70's look SBC, i.e the manifold would have been a Tarantula or a C3BX, or even a dual quad or six pack.

[mag2555]

Just like anything else that your flow testing a given area at the flow numbers seen depend on the test pressure / depression that was used.

If a test that was done at 10” and showed 150 cfm was then done again at 28” you would then see 250 cfm, and on top of that this is all tempered yet again by the air speed seen during the test.

This is what you need to make as I did many years ago to set on my flow bench and 100% prove to myself empirically how much air can pass thru a fairly streamlined orfice .

This was equal to 2.200” sq in and flowed close to 290 cfm @ 28”

If you could get 290 cfm out passed the intake valve and into the chamber then you would have the potential of making 596 hp at 100% VE.

[mag2555]

A well thought out race motor should make 115% VE. ( many hi end motors make more! ) which could tack on another 85 to 90 hp to that 596 number.

[Tom68]

Just like anything else that your flow testing a given area at the flow numbers seen depend on the test pressure / depression that was used.

If a test that was done at 10” and showed 150 cfm was then done again at 28” you would then see 250 cfm, and on top of that this is all tempered yet again by the air speed seen during the test.

This is what you need to make as I did many years ago to set on my flow bench and 100% prove to myself empirically how much air can pass thru a fairly streamlined orfice .

This was equal to 2.200” sq in and flowed close to 290 cfm @ 28”

If you could get 290 cfm out passed the intake valve and into the chamber then you would have the potential of making 596 hp at 100% VE.

I didn't mention it but I guess we'd be talking offset pushrods and aftermarket heads for that port area, since they neck in straight after the opening, still even with standard pushrod location both points would outflow the curtain area I guess ?

[mag2555]

Well if your taking aftermarket heads and offset push rods then what size valve are taking about along with the amount of valve lift to calculate the curtain area, 2.05” , 2.08” ?

[Tom68]

Well if your taking aftermarket heads and offset push rods then what size valve are taking about along with the amount of valve lift to calculate the curtain area, 2.05” , 2.08” ?

Your choice, thinking of the pinch for the pushrods I should have called a narrower port opening.
So then we'd be looking at early 70s spec motors with current roller cam options.
Maybe 400 hp streetable and 500 ish race without going to a Tunnel ram.

Would we add 50 hp for offset pushrod width ports with 2.08 valves ? Assuming the pinch point is a restriction to HP.

[steve cowan]

How much Horsepower can we get through a Felpro 90314 on a 350 ?
Lets call the port size as 2" x 1.25", Felpro lists it a little smaller.
How much HP can we make NA as a race motor ? and how much as a streetable NA motor ?

Back when all we had was Fuelie heads that was your reliable gasket grabbing port dimension, Grumpy and Co would have pushed it far beyond that of course.

I guess we could also accept raised port options with the same port face dimension, since we could use spacers along with a milled down distributor mount to get there.

Lets call it a how much horsepower with a 70's look SBC, i.e the manifold would have been a Tarantula or a C3BX, or even a dual quad or six pack.

You would probably have 2" or less at PRP,when you go up in valve sizes and start calculating throat sizes (90%max) you end up with arse about face port.
A good scenario is throat being smallest area but in a 23 degree head it won't happen.
Another issue is what happens to chamber/ bore shroud, bowl size all get blown out of proportion.
I think my 383 with the small head/ valve deal is a reasonable example, put duration in the cam and it would run on pump gas no problem.

[Bill Chase]

How much Horsepower can we get through a Felpro 90314 on a 350 ?
Lets call the port size as 2" x 1.25", Felpro lists it a little smaller.
How much HP can we make NA as a race motor ? and how much as a streetable NA motor ?

Back when all we had was Fuelie heads that was your reliable gasket grabbing port dimension, Grumpy and Co would have pushed it far beyond that of course.

I guess we could also accept raised port options with the same port face dimension, since we could use spacers along with a milled down distributor mount to get there.

Lets call it a how much horsepower with a 70's look SBC, i.e the manifold would have been a Tarantula or a C3BX, or even a dual quad or six pack.

Trick flow as well as speedway have aluminum repops of the old fuelie heads, with some hand work and paint they can be made to look like the originals. Surprised nobody here has got their hands on a set and taken them to extremes. The speedway piece is around $650 per head, not sure about the trick flow deal.

[steve cowan]

20220601_162949.jpg

How much Horsepower can we get through a Felpro 90314 on a 350 ?
Lets call the port size as 2" x 1.25", Felpro lists it a little smaller.
How much HP can we make NA as a race motor ? and how much as a streetable NA motor ?

Back when all we had was Fuelie heads that was your reliable gasket grabbing port dimension, Grumpy and Co would have pushed it far beyond that of course.

I guess we could also accept raised port options with the same port face dimension, since we could use spacers along with a milled down distributor mount to get there.

Lets call it a how much horsepower with a 70's look SBC, i.e the manifold would have been a Tarantula or a C3BX, or even a dual quad or six pack.

Trick flow as well as speedway have aluminum repops of the old fuelie heads, with some hand work and paint they can be made to look like the originals. Surprised nobody here has got their hands on a set and taken them to extremes. The speedway piece is around $650 per head, not sure about the trick flow deal.

I have a pair of the trickflow camel backs I am doing at the moment looking around 530 hp 383 sbc.
The pinch is tiny,max is around 1.85" without welding.

[Bill Chase]

Bet that's a lot more fun than grinding an old pair of 461/462 iron castings? Imagine just the modern combustion chamber alone would make the switch worth it?

[steve cowan]

20211008_161048.jpg

Bet that's a lot more fun than grinding an old pair of 461/462 iron castings? Imagine just the modern combustion chamber alone would make the switch worth it?