4- barrel for a 306, check specs & comment

[blykins]

The Victor Jr's have always been towards the middle of the pack for a good performance out of the box head. The ones that are towards the top (without going to a Cleveland style head) are the AFR heads, the TW-R, TFS High Port, etc. However, as you stated, the Twisted heads require a piston change.

You posed a situation earlier where you would use the Vic Jr's for the 306 and you would buy a higher end head for the AFR....that's where this idea stemmed from. The AFR 185/205 head would outperform the Vic Jr heads without really breaking the bank.

I would imagine that it is the shape of the port on the AFR. As you said, it's a smaller volume that flows exceptionally high. Low lift and mid lift numbers are high as well. I can't really say exactly what it is, I've never seen a port cross-section between the two.

[YerDugliness]

Originally Posted by blykins

The ones that are towards the top (without going to a Cleveland style head).....

This may be a bit OT, but, Brent, would you mind expanding on your reference to the Cleveland head? I've been a fan of the 335 (and 385) series Ford engines ever since I had a 351C-2V in a 1972 full size Ford Custom 500 that would walk away from SBC's with 4V carbs.....my dream "replacement" engine for my Cobra is an 8.2" deck height "clevor". I know, there aren't a whole lot of good domestic intakes for that clevor (Edelbrock makes one in an RPM model, but no Air-Gap that I know of, and no single plane models, either). The Aussies are WAAY ahead of us on the canted-valve heads, having had them for so much longer than we did.

My theory is that the Cleveland heads flow better b/c as the canted valve is opened by the cam it moves away from the cylinder wall, thereby essentially "unshrouding" the valve head and increasing the flow compared to a standard head.

What do you recommend for a SBF "clevor"......carbureted, of course!

Cheers from Doug

[blykins]

The Cleveland heads make a lot of power. Even the old 4V style heads can be ported to really cut the mustard.

If you chose to go with the old iron stuff, you can make a 4V head flow about 310-320cfm. Then you have a choice of 4V intakes: the Holley Strip Dominator, the Edelbrock Torker, or you can even adapt one of the new CHI intakes. The 3V intake has a port dimension that you can easily fit inside of a 4V port.

If you go new aluminum, the CHI 3V heads will absolutely make the power. AFD also makes some very nice aluminum heads for the Cleveland. Both of these companies are Aussie companies.

You also have a choice between the various Yates heads. Most of those have really big port volumes, so it's not good for a small cubic inch engine...plus the chambers are really small, so static compression ratios would be high.

There are various intakes available for each scenario.

If a budget wasn't a factor, a 351W based Dart block with a large stroke rotating assembly (445-460 cubic inches) with a set of CHI 3V heads, a single plane CHI intake, and a mild street roller cam would be close to or slightly above 700hp.