What are those 12 pt bolts from the block into the head? Extra head bolts?

Yes.

And they suck to do lol

What block is that ?? bushed lifter bores, who did the machining

That pic I put up was an entrant to the Engine Masters competition some years back.

Most, if not all, aftermarket blocks have the provision for that extra head stud...many aftermarket cylinder heads do also.

Just up your alley. Typically a rectangular port intake will be used and the floor of it's runners epoxied up, and then matched to the heads.

There are only a few companies that get/use that cylinder head....you won't see it in the Brodix catalog but it is available.

I have the flow #'s here at work some where. If I find them, I'll put them up.

Edit in, found them:

Runners average 301cc


Lift / Intake / Exhaust CFM at 28"H20
.200" 170 126
.300" 250 177
.400" 307 212
.500 347 246
.600" 373 267
.700 384 279
.800 388 288

we'll be releasing our new "Oval" port soon...stay tuned for details!!

Ok so anyone interested in purchasing AK Racing/Promaxx can refer to my classified add in the engines/parts section!! thank you everyone!!

Count me in on a set of the custom fit and ready to go Promaxx 320 heads.

Thank you Steve, you won't be disappointed!!

Nice to finally meet Rob (Phragle) keep me in the loop with your build... thanks for sporting the AKRacing Supercharged cylinder heads!!![ATTACH=CONFIG]565675[/ATTACH][ATTACH=CONFIG]565676[/ATTACH]

How much is it to ship a set of heads to say 49675. Just curious. Nice ad you took out in the classifieds btw.

I will call UPS in the morning

Perfect. I'm glad your here for us. You also sell springs etc correct.

I do indeed

Just got .700 numbers from Jim today via tx. No pipe and no raised floors yet. Exh 300, Int high 390's. Will get more info later but we were both in a rush.

the exhaust will come up big time even with a small straight 4" pipe no bend... even more so with a 12" with a 90* bend

At 407 cfm on the intakes at .700 as of today.

Jim got back on my heads between projects. He's not done yet but txt over some numbers Saturday.


Exh .200-157
.300-240
.400-315

Int. .500-370
.600-404
.700-424
.750-431

Raised the floors

Should have all the number no later than next week.

Has Jim sent you the rest of the numbers? That's pretty impressive, from what I've seen it looks like they noticeably better than the CNC version from ProMaxx. What size did the intake runner end up being? That .4 exhaust number is better than most heads at .8.

Those exhaust numbers can't be correct are they? Those are as high as a typical intake runner at that level. Did Jim split the intake and exhaust numbers by mistake, when really, those are all intake numbers?

Good catch mike I screwed that up. how I did that I have no clue. Should be posting exh this week.

[QUOTE=getrdunn;4588125]Jim got back on my heads between projects. He's not done yet but txt over some numbers Saturday.


.200-157
.300-240
.400-315
.500-370
.600-404
.700-424
.750-431

Raised the floors. (Corrected on 10/29/17)

Should have exh this next week.

Ha, I was going to say, those are some insane flowing exhaust ports. My heads have a strong exhaust port, but they are not flowing 315 @ .40

No, at 0.400" they should be around 248cfm, if these heads are based off the AFR exhaust. 297cfm @ 0.700"

Mike knew I misprinted but wanted to make note of it and have a little fun at the same time.

I noticed the promaxx 340 cnc head which probably has same exh port as the 317's flow like 300 @ 700 so I'd say very similar although the same 340 cnc head intake flows 398 at same lift. I'd like to see 315 @ .700. I recall Jim not real pleased with the out of the box exhaust numbers. If he can work his magic on those as he did the intakes will be a big thumbs up. At the very least more options regarding aftermarket.

Here's a their 340 cnc head flow numbers below:

ProMaxx BBC 340cc CNC Ported (Bare Heads)

Specs:
2.300"/1.880" valve sizes,
121cc-127cc chambers(Your Choice)
340cc Intake Runner

Flow Specs @ 28" w/2.300"/1.880" w/30* Backcut valves

.200" .300" .400" .500" .600" .700" .800" .900"
Intake 172 267 318 358 383 398 409 413

Exhaust 139 190 236 265 285 300 304 307