Wallace says. 4.030 bore X 3.75 stroke at 5500 rpm needs a 1.93 minimum cross section to not choke. AFRs 180 head has a 1.810 minimum, there 195 head shows 1.905 minimum.

 

I was told that with a mild cammed 383, less than .500 lift and under 5,500 RPM limit, AFR 180. Anything over .500 Lift and over 5,500+ RPM redline (6,000 RPM + really), AFR 195 as a very broad guide....by my expert builder when I built my L-82 355..................I asked for Sh*ts and giggles if I decided to scrap the L-82 forged crank and go 383, which I did not, based on his advice for what I wanted....best decision ever.....

 

4.030 X 3.750 using a 1.81 minimum CSA chokes at 5,169 rpm

 

Mamo that came on speed talk offten and made current eliminator AFR cylinder heads highly recomended 195 heads on any 383 and recomended further the race version of it. Makes zero difference to me what head anybody uses, but then what would the guy that actually made and extensivly tested them know !!!

 

The math doesn't lie, go with the calculator.

 

Man that made wallace knows what he was doing. But more important man that made the heads came on speed talk pretty regurly said that not me.

 

you need half the displacement in port volume as a general rule of thumb. BUT, that is to get max power at full throttle. if you are not taking it to the drag strip, a bone stock small valve head will run well. they put those little round ports on 454's and the trucks run good forever. actually improves 1500 to 4000 power. I have little round port heads. they sit in the garage as spares for the big slow boat. once I get a big block in the vette, it is gonna have rectangle port heads even though they are too big on paper until 6000 or so.

 

never saw a 396 /375 hp taken out by a a 325 hp or 350 hp with oval heads and the .520 lift solid cammed 375 hp cam was a joke by todays standards. Bottom line bbc needed the big valves. Thats one big problem with big small block builds today way under valved for there size in 23 degree heads. Had 396 to 454s used both oval and rectangle with factory chevy cams and aftermarket. Oval port never seen an advantage even on the smaller 396. Maybe if i had put the bigger valves of the rectangle in the oval port. Used both closed chamber and brand new over the counter LS 7 open chamber iron heads. Nice time period when things were cheap in cost.

 

Use the 195's.

JIM

 

 

kind of what I was saying. we are not driving 40 miles to work thus needing to optimize fuel mileage at 2200 rpm. and unless we are trying to get a small block into the 10's optimizing port size for 6500 rpm is also not a big priority. it is what you want it to be. and 195 works good for 383's. don't go to much cam, but you don't want it to idle like an Impala either...

 

years ago AFR and Tony Mamo talked to me. I was on their product tester list and I could get their heads at cost. Tony really wanted me to use the brand new 245 cc heads on my solid roller 427 sbc and years before I proved that 227 cc heads were just a little bit big for 383 motors and the 210 cc were the best for sub 7500 rpm

the sad part back then is that I didn't have lots of disposable income to buy up a bunch of different head models like 195, 220, 235, and 245

 

There's a LOT to a head other than just port cc's. It's 'where" those cc's are within the port that make a difference. The 180's would be a choice for a mild 350......the 195's are definitely not a problem for a milder 383 etc. They are just good solid heads that will make power and drive well.

Heck....I did a 388" for a buddy in a '65. He's got a wide ratio and 3.36's. The thing will idle away from a red light literally with almost no throttle....and it's got 215cc heads and a single plane intake.

JIM

 

Math doesn't lie...but it also does not simulate real life without every variable plugged in either.......
Math does not count for any venturi effect....or velocity relative to piston position.
Without getting into a bunch of ***** that nobody understands.......go with the 195 AFR or 200 Dart Pro 1 Platinum.

Jebby

 

Also AFR are about the best you can get without going exotic and or custom ported. Of course the Brodix people will argue. Patriot and pro comp people...they argue how much they saved.

 

Guys,

Maybe I can help here.....there is no one head fits all.

The correct head choice is application sensitive always (and to some extent who's azz is in the seat and how they typically drive their vehicles).

The following is a general type of statement but also fairly representative and I will focus on the AFR line up of head because as their designer Im a bit partial to them.....LOL

A 195 is hard to beat for a solid all around street engine with a mild or moderately sized HR cam.....more aimed at the conservative driver that spends most of his time under 6000 RPM

A 210 is a good choice for a hotter street strip application.....slightly larger cam and more RPM.....the guy that wants to run it up a bit and spin it 65-6800 RPM when he races it. Still a great choice with a conservative cam if your looking for a head you can get more aggressive with later.

Next would be either a AFR 220 or an AFR 227.....this is the best choice if your building more of a strip/street application.....a Friday night bullet kind of application and best suited to an SR cam that will allow 7-7500 RPMs. You can make big power with the right set-up here but naturally your lower end power will suffer and its more heading towards a race build than a street build although still easily street driven given a manual trans or a stalled auto with (potentially) some aftermarket rear gears in the mix.

I can help design an entire package for the OP or anyone else reading this and supply the cylinder heads spec'ed with the correct springs and chamber volume etc., custom cam, ported intake manifold.....carb.....valvetrain etc.

Please feel free to reach out to me if I can be of assistance. Naturally Mamo Motorsports is a dealer for AFR products and I can be very competitive with my pricing etc.

Hope some of you guys found this post informative

Regards,
Tony

 

Thanks for your time and help to others mr mamo. Im bumbed that the owner of speed talk has died. Can olny hope his wife will try to run it or sell the rights to someone else. i love vettes will always look at this forum but the amount of knowledge that came on speed talk was unreal.

 

Wow.....this is the first Im hearing about Don's passing.

I have a good feeling that his wife and family will do whatever they need to in an effort to keep that forum active.....its a part of his legacy.

Spoke with him on the phone a few times but didn't really know him

Very sad....my condolences to his family and friends

Sincerely
Tony

 

DItto, that site can be humbling with all the brains on there, I bet it stays up. The information there trumps about any enthusiast forum around.
Good to see you drop in Tony. Those Darts you did years ago are still rockin.

 

Something quick like that very hard on a family unexpected no time to except its coming. Ya about a month ago i noticed at the top of engine tech it said... Read only while i fix a database problem. Been stuck on that page at least a month. Found out another way that the owner had passed. There many on this forum above my pay grade but speed talk its people from nascar to pro stock come on it. John kasse 13 time ahra engine bulider champion darion morgan another pro stock engine builder. People that make camshafts. Machinest even a guy with bonneville record old triumph.