flow results
 

LS 317 head with 2.00 intake and 1.55 exhaust

last night I did 2 ports, one the runner only with carbide cutter so it has dimpling similar to golf ball

the second was runner, bowl and chamber and finished with sand paper roll

Neil came over to help and verify results

stock port
.1 70
.2 144
.3 195
.4 230
.5 233
.6 236

runner only with carbide cutter
.1 75
.2 146
.3 200
.4 242
.5 265
.6 276

whole port and chamber sand rolled
.1 71
.2 143
.3 203
.4 242
.5 272
.6 280

the hump from the rocker bolt was not removed nor was the swirl hump near the guide on any port

I use to remove the swirl hump and I'm not sure how much of a difference it makes but Dupree has a set I did for him a long time ago that I will test

all and all, the 40 cfm increase should equate into a 60 hp increase on a mild build, 80 hp on higher comp, big cam engine

one more thing, Neil brought over 2 efi intakes, IMO, the intakes could use a gasket match, or better yet, just make the whole port wider like I'm capable of doing with carb based intake setups matched to the felpro paper gasket

my heads?

no, are you in a hurry for yours? lol

no, lol

I dont know anything about flow numbers or porting but those numbers seem high to me. I got this from AI's webpage

"Typical gains for our CNC work are in the 20-30rwhp SAE range over the as cast 241"

Those numbers seem more inline to me, but I know zero about porting.

Nice work. how much you charging for the work?

Agreed. Definitely high IMO. I gained 55rwhp with my AI 226 243s over stock 241s and that is BIG jump for 243s over 241s. SCR was 10.1:1 with 241s and after was 11.5:1 with the 243s. I'd say 30-35 would be very respectable and about what I would guess over stock 241s with those 317s.

cylinder head flow determines what HP an engine is capable of making. when I say HP I dont mean rwhp numbers either.

the simple formula is 1.5 hp per cfm for a hot street engine
2.0 hp for your run of the mill cookie cutter race engine
2.2 for balls out, high comp, low tension ring, gas ported piston type deal

so a 40 cfm increase x 1.5 is a 60 hp gain. If you dont make that 60 hp gain then there is a reason like the cross section area of the intake is the restriction

that brings me to some more heads that I flowed today

I'll start with Texas Speed PRC 243 cnc heads with 2.0 valve

.1 72
.2 137
.3 199
.4 241
.5 284
.6 307

these heads have the rocker bolt hump and swirl hump removed, also the cross section of the port was wider than stock. if you bolted a stock intake and gasket to this head, it surely would limit its potential because the intake and stock gasket is smaller than the port


also brought over today was an AFR 225 cathedral port head with 2.08 valve

.1 75
.2 141
.3 203
.4 250
.5 290
.6 319

Also flowed today and I'm completely embarrassed about this because I ported these a few years ago, were 5.3 heads with 1.88 intake valve

.1 70
.2 134
.3 190
.4 216
.5 245
.6 253

what does your can run at the track and at what weight?

Makes more sense, thanks. I was just asking because I dont know. I had one set of heads ported by Texas Speed and they cracked all the way through the runner. After that I have always been gun shy. I have also seen more "ported" intakes make less hp than before they were ported.
Do an increase in cfm always equal more hp?

i would think not always. maybe the more cfm would allow for less velocity which i guess could cause some adverse effects.

My H/C/I LS1 ran a best of 11.79 @ 126.5 mph at 3550 raceweight with me in it 2.01 60 ft.

no, the cfm does not always make more HP. velocity is critically important, the reason for such long runners on newer V8s. swirl into the chamber is also very important, one of the reason why i'm now gun shy about taking the swirl hump out.

the Texas Speed port is really big. If I can get Neil over here this week, I would like to do some intake bolted to the head testing. my feeling is my port job with a smaller runner will be equall in CFM to the Texas Speed head but mine will have more velocity which I can't measure yet because all the little add ons cost money and I have none

the smallest port with good flow equalls the fastest time down the track

Your Horsepower computed from your vehicle weight of 3550 pounds and MPH of 126 is 583.66

583/2.0(hp per cfm)=291cfm

Cool.. the car dyno'ed 474/428 to the rear. Here are the heads with flow numbers http://advancedinduction.com/LSX/AiL...cGMLS2Head.php

what intake was on your car?

FAST 92 unported. Nick Williams 92mm tb. FTP 98mm air lid.

i need to see one of them. but you can see how the math works out. simple

Gaskets are in,so whenever you want the heads...let me know

any night this week would be fine except when Tatu Baby is on TV which is tomorrow