A few years back, Doc on the webrodder site began a 235 stroker project, bring it out to 255", with some modern tech put into the build. They did some flow testing on a stock intake port, reviled that terberlence in the port began as low as .250" of valve lift, got really bad past .450". They thought porting the entire port would be cost-prohibitive, so went with pocket-porting above the valve seat. I don't recall the details, but believe they picked up flow by 10-15 CFM. Think they stayed with the 1.88 valves, didn't test the 1.94 PG valves.
Sadly, Doc has had some health issues and the build wasn't completed and dyno tested. All 8 parts of the build have been deleted.:(
I do know that Billy at Comp Cams was working on a dual-pattern cam with 256 intake duration, 260 or 262 exhaust. Tom Langdon has a dual pattern cam available, but don't have the specs. I think the idea behind both cams is to close the intakes earlier to build DYNAMIC COMPRESSION and help the crappy exhaust port with more duration, like Mcguirk did.
A local performance engine shop did my pocket porting for $150 4 years ago. From what I've read, the last 1/2" of the port is the most critical, should not be any larger than 80% of valve size. If I was to start over, I would go with a 15-deg. back-cut on 1.94" valves, pocket-porting and port clean-up. Maybe try a cam change, Edelbrock 500 carb too! Can't say it would produce a huge seat-of-the-pants difference, but every lil' bit helps on these ol' turds WE LOVE!!!
For now, I'd try a 500 4-bbl, Langdon's HEI dizzy with VACUUM ADVANCE. To get more than that on the street, your looking at work and $$$ for a turbo or blower set-up to fry the tires - anyplace, anytime!!!
https://www.inliners.org/ubbthreads/images/icons/default/grin.gif I'm a newbie here, but have enjoyed sixes since I bought my '53 Chevy PU back in 1974. Also have a '57 Chevy 150 2-dr. with a 3/4 cammed 235, Vega 4-sp, 3.08 gears, with a 261 in the planning stages. A very lo-buck, VERY FUN ride!!! Hope my $.02 offers food for thought...
Best Wishes, Tim
