Jay's dyno testing with carbs (question for Jay)

[My427stang]

Jay, years ago I remember you and Royce testing a bunch of carb combos.  If it's in your book....just send me to go read it, I have it LOL  However, if not, do you have those results somewhere?

I am looking for what the dual 450s did, what bigger carbs did, and what you tested them on.  Even better would be any fighting you did with the fuel curve on any of the combos. 

I am specifically asking for a 550-ish HP stroker, and trying to compare apples to different apples

Thanks

[jayb]

Ask, and you shall receive, Ross 

In the book, the carb comparison data is on pages 223-226, charts are on pages 225 and 226.  There is only one chart for a 2X4 setup, and it is a lower HP engine.  However, a few years back I dynoed a 390 stroker for a friend of mine that had stock Edelbrock heads, a small solid roller cam, one of my intake adapters and a Weiand tunnel ram.  My friend was convinced that the 450 carbs would be the way to go, so he had some worked over by a local carb guy and brought those.  After we dynoed with those the results were disappointing, so I swapped on my set of 660s and we ran again.  The results are in the chart below; it was a big difference.  Unfortunately I don't have any data on what jets we used, but there were several runs with the 660s on the dyno, and the A/F numbers started out lean, but gradually came in, so I assume we were doing jetting changes along the way.  Hope this helps - Jay

[Drew Pojedinec]

This whole "smaller 2x4 carbs=better" scenario has been a source of annoyance more than once for me.

Ford in their inifinite funding, decided on two 600's for their street 427, later they used dual 715's.  Now guys are building 482ci strokers and asking me about dual 390's or 450's because of some stupid Holley calculator.  Lol..... right right right.  The Holley calculator has one purpose, and it is to keep annoying people from calling the apathetic help line.

When asked, I'm sticking to my guns here:
>550hp dual 600's
>550hp more race oriented, dual 715's
<550hp street, dual 715's
<550 full race, 660's
Big cubes, big power street, dual 780's

If you are a tinkerer, you can blur those lines a good bit more.
The one place I like to use 1848's, 1849's or -C carbs is for the 390/410 mild cruiser that just wants the glam of 2x4's.

I am curious about dual 850cs's vs 660's with much larger (500ci + full race) engines, I just don't have any real track data for that.

[jayb]

You will be happy to know that I plan to test 660s vs the center squirter 850s you did for me a while back, when I get my dyno engine back on the pump to test my cylinder heads.  Should be an interesting comparison...

[Barry_R]

You will be happy to know that I plan to test 660s vs the center squirter 850s you did for me a while back, when I get my dyno engine back on the pump to test my cylinder heads.  Should be an interesting comparison...

Test dual 1050 Dominators and the rest won't really matter....

[blykins]

You will be happy to know that I plan to test 660s vs the center squirter 850s you did for me a while back, when I get my dyno engine back on the pump to test my cylinder heads.  Should be an interesting comparison...

Test dual 1050 Dominators and the rest won't really matter....

Or 1450's.....



To follow Drew's discussion, I use a lot of the 725cfm carbs on the FE 2x4 setups.  They will support 725 hp easily. 

[wowens]

Sorry for the 2nd post on this,  but.
I was amazed 50 years ago at what Smokey was doing but that thing he dreamed up is unbelievable now and that was a long time ago.

[Drew Pojedinec]

To follow Drew's discussion, I use a lot of the 725cfm carbs on the FE 2x4 setups.  They will support 725 hp easily.

Once you get into dual Dominators, it is really a whole nother engine with a vastly different purpose.

Regarding the 715/725, I really wish Holley had made a ton of 1 5/16, 1 3/8 venturi, 1 11/16 throttle bore generic downleg carbs.  I find them to be a very good size. Seems like they went from 600’s right to 750’s with slim pickings in between (for VS)

[Drew Pojedinec]

You will be happy to know that I plan to test 660s vs the center squirter 850s you did for me a while back, when I get my dyno engine back on the pump to test my cylinder heads.  Should be an interesting comparison...

I kinda have the view that bigger carbs will generally make more dyno power. Nice to test them in a car.
I have considered making a set of 4160 850 cs’s for my own tests, but I really don’t have enough engine.

[fastf67]

I believe drew has the correct statement as far as 450s vs 660s vs ect.
If you have enough engine! Most fe engines built today are, as dont see alot of 352 stock builds with duals. 450s worked great for my (mexican block/cleveland head) boss 302. Ya oops, 16 yrs old with 1978 technology also.  hahaha

[Posi67]

All I can add is my 660's that had the 850 mods done to them are marginally quicker than my 600 QF Vacuum carbs. (2x4) Tried them both on my old 427 and the current 428 with the same result. Both are high 9 second engines so it seems like a fair observation. Fuel mileage does suffer badly with the 660's. People waaaay… smarter than me have suggested a too big carb can look good on a Dyno but not go down the track well. One only has to look at the power a Super Stock engine can make with a factory sized carb. Pretty sure Blair can elaborate.   

[My427stang]

Thanks!

I have used a few of the mechanical 450s, but they were on nearly stock CJs, a CJ spec 410s, and the largest was a 282S cammed medium riser 454, they worked great but never dyno'd.  These are repop 1848 465 vac secondaries made to look like original Ford, but essentially the same carb in terms of airflow I believe.

I am going to try a set of Drew's big carbs, and we'll run the 465s, and if it makes sense to do so, I will spin up a pair of 1850-2 600 mongrels I have to split the middle.  I'll let you know my dyno results to add to the list. 

I really appreciate it, and it certainly looks like it's worth the time to try them

[Tommy-T]

Jay, years ago I remember you and Royce testing a bunch of carb combos.  If it's in your book....just send me to go read it, I have it LOL  However, if not, do you have those results somewhere?

I am looking for what the dual 450s did, what bigger carbs did, and what you tested them on.  Even better would be any fighting you did with the fuel curve on any of the combos. 

I am specifically asking for a 550-ish HP stroker, and trying to compare apples to different apples

Thanks

I seem to remember some fiddling around with a 3 barrel Holley in the carb flogging. Can you elaborate on some of the ancient "big" Holley mess'n?

[Falcon67]

>This whole "smaller 2x4 carbs=better" scenario has been a source of annoyance more than once for me.

LOL.  "1200 CFM is too much for a 302!"  says the internet and Facebook.  I was just able to get out Sunday and test the Falcon with the new Meziere water pump and fabbed alternator mount.  Along with the dual Holley 600s with some tweaks (from racing fuel systems discussion) on the tunnel ram.  Both List 1850s, eBay specials.  This is a 351C, stock stroke, 30 over, decent hydro roller, 10.5:1 4V closed iron heads, 4.56 gears, 4500 stall 10" converter.  Only had some 87 octane fuel, 2 gallons in the cell so it was once around the block.  I gave it a good punch just because and the thing jumped up in the air like it wanted to fly.  2500 to 5K+ in a blink.  Will track test it with a LC2 datalogger and the proper VP110 mix at the TnT on 6/6.  But the butt-o-meter says "fun times!"

>Or 1450's.....
Now you're just showing off.   

[FElony]

What about, at 400-450 street hp, a pair of 4180 annulars for manners?