The real jewel of the 308 head is the exhaust port. Gone is the restrictive bend in the flow path, and even though its a dinky port opening compared to the J or X heads, it always outflowed them. Where the other would peak around .400-.450 lift the 308 would continue to get better in the upper lift ranges. Several years ago I saw an article one of the good shops of the day put out on the 308 that was very interesting. They took a bonestock 308 and an X head ported them to as close to identicle numbers as they could, with same size valves and same cost (hours) to a potential customer, then flow tested them and finally bolted them on a solid lifter cammed bracket type 360. The flow numbers on the 308 were similar on the intake side, but the exhaust number on the 308 were much better, still climbing past .600 lift. On the dyno the 308s made 12 more HP, but almost 30 more FT LBS of torque. The guy said we'll prep a set of whatever a guy prefers, but the best bang for the $$$ spent is obviously the 308. The 308's I had on my 414 only flowed like 190 on the exhaust at around .620 lift, but the car ran great, at 3300 lbs shifting at 6400 ran 10.45 @ 127 (chippin real bad ) and ran 6.59 @ 104 in the 1/8. The chamber is as plain as any other factory head. The "magic" with these heads is in the pushrod pinch area and the raised exhaust port. When they were readily available, these are what you'd find on most stock class cars.

The exhaust ports on old LA heads only flow about 134 CFM unported.
At least these have a floor in them.

Too bad Mother mopar only took a fraction of Larrys development into production. Pretty par for the course.

"The "magic" with these heads is in the pushrod pinch area and the raised exhaust port" so would knocking down the pinch work to kill off the swirl on the heads and decrease the flow?

with strokerpost, the only real magic in the 308 is the exhaust port, which coincidentally is basically a magnum exhaust port.

the pushrod pinch is more a function of the larger PR hole needed for the roller cam setup (taller lifters/shorter PR need more clearance) and the fact it's easier to machine a round hole than a slot....

really, I don't think there's a whole lot of "swirl port" technology in the 308's, I'm thinking it's more of a marketing gimmick.

the bulk of the R&D being put into production is the magnum head, with it's "B" shaped chamber with dual quench pads, exhaust port, etc....I'm trying to remember, I _think_ my mags had little wings cast into the roof of the intake port to induce swirl and tumble, too...

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would knocking down the pinch work to kill off the swirl on the heads and decrease the flow?

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In my opinion, it is a ballancing act. Removing the rounded pinch completely will all but eliminate the swirl effect. When I have ported these I have tried to retain the the overall shape of the runner but also increase the cross sectional area. I have talked to some (and experienced it myself) that removed the pinch all together and their quarter mile times went backwards.

I think in almost every performance application you want to open it up from as-cast, at the very least, removing the valve cover bolt bulge and smoothing the pushrod and divider wall. (Remember these were designed for an OEM application that almost never see more than 4500 RPM). On more serious motors, I have moved the wall over as far as possible but kept the round shape with an increased radius.

The larger the dispacement or higher the RPM range, the more increasing the cross section will help.

My understanding is that the 308 exhaust bowl (and short turn) is based on the W2 design.

Note: I am not a cylinder head design expert. I am offering my opinion only.

It would be great if one of the chrysler engineers that worked on this head would chime in. (I wont be holding my breath)

"It would be great if one of the chrysler engineers that worked on this head would chime in. (I wont be holding my breath)" Larry Meaux was the guy that worked for Mopar in upgrading these heads. His hands were tied,but he gave mopar the exhaust port,although cost and other factors keeped lots of improvements out of the final product. As far as removing the pinch,depends on the combo as well as the rest of the port. Contact Larry@maxracesoftware.com ,he's one of the sharpest guys you'll every meet and a fantastic head porter.

Same port with a home made valve.

.100"_______57.7
.200"______122.3
.300"______176.2
.400"______205.2
.500"______203.0
.550"______200.7
.600"______198.5
.650"______199.6
.700"______200.7

Rev Search <Jessie> has lots of time messin with iron Mopar heads, He has dyno results also, Great guy with lots of info

This was just an FYI post. I wasn't looking for pointers.

Looks like to get good flow out of the la heads the V/G needs to be milled way down into the port roof and then blended, Did Vic move the pushrod over on the intake and epoxy the pinch?

#2. Pretty pinchy still. He did an awesome job he is the man. I have more pics whatever else you want to see on these heads. I am sure Vic has way more pics of different heads and jobs and all that.