Iron RAIV porting
 

I am having the good fortune and pleasure of porting for a good friend and drag race pal a iron RAIV head to match one that has been ported already that he came into possession of.

The head that has been ported is an original production one ( the other over the counter) and has been said to have been ported by our great recently departed Pontiac guru Pete McCarthy.

This ported head was set up for a 2.15” 30 degree seat valve and flows very well for its 1.77” to 1.80” throat that was used seeing that these heads can go 1.850” safely as compared to trying that throat size in a iron D port head.

Here are the stock flow numbers and the as received ported flow numbers @28”

I have not CCed an intake port yet, but will do so and post that up before the end of the weekend.

.100”——-84.2——54.2

.200”——-148.1——-148

.300”——-193——209.3

.400”——-213.7——247.4

.450”———————258.2

.500”——-223.7——272.9

.550”———————282.7

.600”——-232——286.2

I will post up some photos and port dimensions later today.

Very cool! Nice numbers

Paul has my SR 614s to look over.

Cool!
Thats what these heads are, a 614 casting.

Mine were SR castings . Got new never used form a local guy. On outer exhaust port untouched had a small casting hole we had to weld. I think with the NMCA "legal" pocket porting and port match they went around 249 cfm. Exhaust was 85% plus. Why a reverse split cam went the fastest of the 4 cams I tried back then. I knw John Angeles in his SS car and John Schloe in his RAIV stocker both ran single patterns.

I might add your very nice 614 heads

Steve what exhaust valve are these heads set up for?

I remember working on a pair that were originally set up by Butch Elkins and they used 2.08/1.81 valves

Paul these are 2.15” 1.77”.

Strange that someone would go with 1.81” exh valves unless you were building a boosted motor and needed a ton of exh flow for a really high ratio.

I have taken D ports up to 240 cfm and can’t see why these 614 exh can’t do 255 to 260 if needed while staying with a 1,77”.

Here’s a few photos and dimensions of the as revived ported intake ports.

The throats range from 1.76” to a tad over 1.77”.

Port height at the flange is 2.390”.

Port width at the bulge averages 1.065”

Port height at the crown of the short turn 2.030”

Port width at the crown 1.485”

The short turn is a 100% complete quadrant of a 1.77” , so it’s layed back a lot!

I know it takes careful decisions to achieve 1.77" bowl throat. Nice.

Can you measure WxH at the pushrod bulge and compare to the bowl CSA?
Just noticed you posted the measures so i can calc. From the looks you achieved a choke-free Pushrod bulge passage so them irons gonna make power.
I use a very long 3/8 extension in the pushrod hole as a (visual) guide for bulge iron thickness, while belt sanding the insulting iron. Two goals being a straighter shot and choke-free CSA beating application RPM-CID choke calc.

Unshroud the intake valve at the Chamber? unshroud the EXH? Helps to sharpie the head gasket CYL to the head too free-iron excess for unshrouding goals.
No touche the EXH ports or flange right?

...really enjoyed my R-96-A port work: an effort in minimalist porting. Makes the iron of higher value!

I agree on larger exhaust valves in them. I had reversion issues running mufflers for the rules. Exhaust ports flowed almost as good on the flow bench backwards as forwards! Heck even my 6X-4s we added 1.77s to jumped way up in E/I ratio. I found smaller header tubes going from 2" to 1 3/4 and the reverse split cam ran the best. It was pretty non responsive to jet changes before that.

282 cfm at only .550 lift, nice. You could make some good power with that.

Sure could, even with a hydro flat tappet.

Very Impressive! Thanks for the pictures too.

Welcome!

Port height at crown 2.030 wow and entry 2.390.

Yes, in fact I will be CCing that port in like 20 minutes.

I will report back when done.

I think the tallest you can go in a stock 6x is 1.7 or so at the crown

Sounds about right if you don’t make the mistake of laying back the short turn too much.

I can check my notes .



So this RA4 port is checking in at 209.4 CCs, so not too far off from a off the shelf Edelbrock.

Why is the 100 number effected so much?

Once you start laying back and as the throat opens low lift goes byby.That .100 is pretty low for 30 degree cut.

For two reason .
Mainly due to how much the short turn has been layed back do high lift turbulence would not case flow regression, and 2 due to the narrow amount of 60 degree bottom cut used in the valve job.

Tomorrow I will post photos of the short turn in the as ported head and as they are in the head I am working on.

The difference will be clear to see, at least for now.

Thanks Steve

To be fair with this head I only tested that one intake port and from what I can see with the other untested ports there valve job does differ a bit which could change things for the better.

Also I only had a 2.11” valve to test that one port with and it’s cut for a 2.15” valve which I now have to finish off these heads with .

I will conduct more flow test over the weekend and report back.

I'm curious what the port will flow with just the valve stem blocking ( insert valve in from valvecover side).

I can try that when I get back into flowtesting mode with what I am doing, but with what I have seen in the passed a well shaped intake port will pick up a added 3% or so above .550” lift.

The port window entry into the valve bowl appears it could be hurting the flow numbers up to .3, then creating turbulence that is cutting the peak flows off at the upper lifts early. The ceiling is likely ported to high in the bowl for how much the short side radius is layed back. I am guessing if some epoxy was added in the ceiling to match the contour of the short side for less turbulence the port would pick up everywhere. Between a better vale job and some work in the ceiling, that is probably going to shoot past 300 cfm.


Very cool to see the work that was done, fun project!

Joe I have to make about .025” correction in what I posted back in #9.

I checked all 4 intake ports and the distance from the crown of the short turn to the roof is 2.003” to 2,007”.