Don't read if you're close minded
- Thread starter Mean416
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justinp61
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Come on Mean416, EVERYONE on this site knows dynos are the spawn of the devil, aren't accurate and can be manipulated to show huge numbers, so the owner can get on the internet and brag!
Now flow benches, they are the gospel, no one on the internet would inflate their flow numbers.
Oh, so You've fit a 4V intake to a 351C with 2V heads instead, & seen the difference. It can be done, & I did it in the late '80's for a fellow gearhead, '68 Torino GT...guess which combo ran better w/a mild 270s° cam, I KNOW the answer, happy 4th
But my overall point is we're building Mopars and we really don't have huge port heads and if the Cleveland guys can get away using 4V heads on 302-351 I'm sure we don't have to worry as much as people do.
Especially people worry about port velocity but seems like not many know how much velocity you need and what port size to cfm to get there, but IF these formulas have any accuracy we seem to suffer from not enough port volume.
Eg.. Recommended ideal velocity is average csa that gives you 260 fps with desired cfm, so say 260 cfm x 2.4 / 260 fps = 2.40" average csa, if the average port length is around 4.95" which Earlie A measured SM port to be that's a port volume of 195 cc we would consider that a vary large port for only 260 cfm, we would hope to get more like 300 cfm out of that port volume which would increase port velocity to 300 fps.
You would have to get like only 225 cfms out of a 195 cc port to get a low velocity like 225 fps which is pretty unrealistic scenario and a velocity of 225 fps is still considered board line usable.
Even a 200 cfm say for a mild 318 = 150 cc for a 260 fps basically a stock 360 head. Seems like we might have not enough volume problem, or put another way too much velocity.
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I went from ported 302's to mildly ported 587's around the same flow (240's) nothing else was changed and it was all top end and lost all the torque under the curve.
I remember Lead69 posting this:
"Very cool thread,nice to see you document this for everyone.I ported a set of 318 heads for a street 360 build with awesome results.I ended up raising the legnth of the roof to the stock 360 port size and reworking the short turn and opening up the bowl to 90% of the intake.Also did the same as you on the exhaust side,original 1.78/1.5 but they did have a serdi valve job.The heads went on a stock 360 shortblock with an actual 8.6 compression,ported performer intake (360 size runners/mild plenum work) 600 holley,cheap headers and an xe274 and was a screamer,upper 12's all daylong with 3.23s in a 70 dart!."
"IMO port the 318 heads,I would keep the valves stock and go 1.51 on the bowl and port match to these gaskets http://store.summitracing.com/partdetail.asp?part=FPP-1243&autoview=sku with this and typical exhaust mods you can gain a ton of power while having a ton of low end and high velocity.I did this to a 360 (kind of an experiment) that wound up at a true 8.7 comp.,xe 274,port matched performer,1in. spacer and headers with stock rocker gear.This engine ran like an animal and made low end like a 383,it pulled cleanly to 6k and made a ton of power,with 3.23s and a 904/2,500 stall it easily ran high 12 cars so I have no doubt it was a 12.80-12.70 combo with 3.91s at the track."
I've always liked the 318 head port form better, just wished it were taller, that's for sure.
Wait, isn't this the thread about Holley Dominators making more Dyno Oats on a BBC & SBC? I didn't introduce the brand F heads/engines, or the sidetrack into Your port flow/velocity thread parallel, but I am addressing it specifically.
BTW, My spitball opinion on the original subject, both engines were capable of using the 1050..the Dominator has a larger dia venturi entry per it's diameter, & throttle bore...a good chance the signal & tuning were superior on the Dom.
It's six pages deep of course it's off track.
Hysterics brought up the Fords, you were debating the OP take on the Fords and I'm adding my take.
Port velocity, carb velocity it's all related.
Ohh definitely the thread long since exhausted the original intent.
My thoughts on the original question....
I think the most obvious possible solution probably is the solution.
1. It's likely that the dominator 1050 flows more than the 4150 based 1050.
2. It's likely that the dominator has better fuel mixing and atomization characteristics.
Without a MAP and intake temp sensor on place it's really guesswork. I will also say...damn it must be nice to get those kind of power numbers out of a dual plane small block.
My thoughts on the original question....
I think the most obvious possible solution probably is the solution.
1. It's likely that the dominator 1050 flows more than the 4150 based 1050.
2. It's likely that the dominator has better fuel mixing and atomization characteristics.
Without a MAP and intake temp sensor on place it's really guesswork. I will also say...damn it must be nice to get those kind of power numbers out of a dual plane small block.
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