[Cliff R]

"All new big buck high power parts people Bolt on during a build when a well thought out stock rebuilt high comp iron head 400 with the right Cam with 3.90 gears in. 3600 lb car can easily dive into the 12s!"

+2

We helped a customer couple summers ago put his 1968 FB into the 11's with a pretty "mild" 400 build. Flat top forged pistons on "H" beams rods, zero decked, ported #62's, Crower 60243 cam, HS 1.65 rocker arms, Rhoads lifters, stock 1968 iron intake, recalibrated 1968 Pontiac Q-jet, TH350, custom converter from us, 3.73 gears, DOT tires. My only contribution to the project was the TH350 trans, custom converter, Q-jet and cam camshaft advise.

First outings netted low 12's with poor traction but over 114mph. Yes, that's not a typo, 114 MPH with a pump gas 400 build, showing excellent potential once some traction was found. He made some suspension changes to get it to hook and went right into the high 11's. Pump gas, relatively smooth idle, great street manners.

As far as cylinder heads go the 1974 #46's and another example of an excellent head and larger chambers like the 4X, 5C and 6X castings. We built a 455 with a set about 10 years ago, never touched them anyplace other than opening them up for 2.11/1.77 valves. On a 455 build they made 440hp/530tq with a Crower 60919 (RAIV clone) cam, stock intake, q-jet, etc.

As for our 1969 #46 heads we tested they were stone stock everyplace, using the nearly 50 year old valves and retained the 45 degree intake seats. High 11's without touching them is flat getting it done in a pretty "basic" 455 build, IMHO.......Cliff

[Stan Weiss]

Steve,
What intake valve angle did you use? Maybe you can talk about the change in low lift curtain area as one moves away from a 30 degree intake valve seat.

Stan

[steve25]

Stan these are 30 degree seats like stock, and in my flow testing / checkouts up to the.380" lift range the curtain area that a 30 degree seat makes Can flow up to 18% more air that a 45 degree seat does with the same size valve.

Above .380" lift or so the advantage of a 30 degree seat will start to nose over pretty fast depending if your running more then a 2 angle valve job as a 3 angle or more seat used on a ported head will start to eat into how big a Throat area you can use.

[walt03]

Originally Posted by steve25

Stan these are 30 degree seats like stock, and in my flow testing / checkouts up to the.380" lift range the curtain area that a 30 degree seat makes Can flow up to 18% more air that a 45 degree seat does with the same size valve.

Above .380" lift or so the advantage of a 30 degree seat will start to nose over pretty fast depending if your running more then a 2 angle valve job as a 3 angle or more seat used on a ported head will start to eat into how big a Throat area you can use.

Steve, what is the second or third angle you use?
A narrow 45*, 050, and a .58 or .60 cut? or just a 30 seat and then drop it down at 90. * like a chamber plunge cutter does.

I'm working on my grandson's 6x-8's and am going to use your chamber mod from what I can make out.
I'm using a 1.69 diameter valve to enlarge the intake bowel chamber and do nothing on the short side, just on the side you unshrouded and the sides of the bowel. Am in going in the right direction?

I thought about radiusing the intake ports at the roof /walls and In dong so was going to raise the roof about .100. I this ok?

Also, I was going to enlarge the pushrod choke point from the mid point of the port to the roof, i HAVE AN AUDIE FLOW BENCH BUT HAVEN'T USED IT IN YEARS.
My grandson convinced this 80 yr old hot rodder to do it again and teach him something he can use going forward.
Last thing, I was going to just clean up the exhaust port that has 1.66 Dia valves.

I used a 1.5" valve for a template and wasn't going to remove the boss in the exh.port after the guide but just raise the roof .100 in the 2 troughs behind the value guide and boss. out to the exhaust exit. Your thought?.
I left my email and cell # if we could talk.


Thanks, Steve

Walt Mucha
Brentwood, TN
wamucha@comcast.net
615-838-6223 cell