aluminum heads

[HeadDoctor]

Bruiser

1) How did you arrive at that C/R? (No guestimates please)
2) What do you use this car for?
3) If you know what you use the car for then you also know what converter to get
A) If it's a race only car then you need an 7" or 8" converter W/ 5000 to 5500 RPM stall
B) If it's a S/S car then you need a 8" or 9" converter W/ 2500 to 3500 stall
C) If it's a street only car then you need a 10" converter W/ 2500 to 3000 stall

4) How do you plan on running 10.5 to 1 C/R on pump gas, when the limitation is 9.5?
5) It's not the static-compression ratio that's important it's the running or pumping pressure, which is determined by the timing events of the cam. On pump gas the limit for this is around 185 to 220 depending on how much ign-timing you run. We have found that 30 to 34 degrees of total timing works best on a S/S engine & pump-gas at about 175 to 195 psi with the cams we run.

6) There are several cams in the post for Brian any one of those will work for you, but in order for me to configure the cam correctly I need real info not guestimates!!!

Denny@JDS Induction Products

[1979bruiser]

i do know that this is a street strip car and i had planed a 3000-3500 stall speed. as for the c/r i can only give you static and no i dont plan to run straight pump gas , at a min 50/50 w/ race fuel as this will be driven fair weather only. im not sure what to tell you for the compression, only what i have i have been told.and w/o a cam i can not get cranking pressure.total chamber volume is 66.50 w/ the piston releifs if that is no help than i understand, and thanks for the help w/ my post.
dan

[82 GT]

Bruiser, your pistons would almost have to be domed for that kind of CR with those large chamber heads....or are they?

HeadDoctor, one of those cams you suggested for me, the 274XE, is the cam I already have. I need either more cam or better heads...or both. I would have thought that the heads I have, with the 1.94/1.60 valves, would be good enough for at least low 12's...maybe not. Would I get more HP just by switching to a solid cam with similiar specs?

[HeadDoctor]

Brian
I know that I put it up there so those reading this thread could compare the one you have to the ones that I listed.

"Want more top end with your heads put that 252-260 Lunati Hyd Roller in it - Have it ground on 108 LSA. " ( Put it in at 100 ICL )

Dan
Static C/R is the ratio of the cylinder volume at TDC verses the volume at BDC

Example:

351 CID /8=43.875 cu. in. times 16.38716= 718.986645 cc's At BDC

TDC= Chamber vol, + Gasket vol, + valve reliefs, + deck clearance, + distance to top ring. If you have a dome piston then you have to subtract that vol from the above.

Chamber= 66.5
Gasket= 9.3 - 4.100X.043
Piston= 7.0 - No dome 2 eyebrows
Deck = 0.0
Tot = 82.8 cc + 719 = 801.8/82.8= 9.68 to 1

Engine tech is all about the math learn the math and you can learn the engine dynamics!!!

Denny@JDS Induction Products

[1979bruiser]

i have a 60 cc head and pistons w/ 2 releifs at 6.50 cc and comes up to 10.5-1

[HeadDoctor]

Dan

Originally Posted by 1979bruiser

i do know that this is a street strip car and i had planed a 3000-3500 stall speed

What diameter?

as for the c/r i can only give you static and no i dont plan to run straight pump gas , at a min 50/50 w/ race fuel as this will be driven fair weather only.

How far do you plan to go on that 50/50 mix?
What happens when you run out?
How big is the gas-tank?
What kind of gas milage do you expect to get with this S/S combo?

im not sure what to tell you for the compression, only what i have i have been told.

With 60cc heads you do have 10.5!!!

and w/o a cam i can not get cranking pressure.

What does it crank now?

total chamber volume is 66.50 w/ the piston releifs if that is no help than i understand, and thanks for the help w/ my post.
dan

Ok - So put the same cam in it that I recomended for Brian or use the 51012 & have it custom ground on a 106 LSA and put it in on a 100 ICL

When you check the heads out be sure they have the good valve springs that have at least 135 LBS closed and 175 LBS open. I use Isky 8005-A springs for these HYD Roller cams set the height at 1.9



Denny@JDS Induction Products

[1979bruiser]

175lbs open?

[antyates]

Pro Comp Is Austrilla, I Have A Set--210cc Intake, 60cc Combustion, Manley Valves, These Are Just Like The Victor Jr Excatly The Same Specs, These Heads Are Actually Good Heads!

[HeadDoctor]

Dan

Sorry Bout that 375 open

[1979bruiser]

thats what i thought , but just wanted to be sure.
thanks head doctor, you are very helpful.

antyates- you have had good luck w/ these heads?

[10sec80cobra]

i sent a pm

[antyates]

yes, real good luck they perform great, Maybe i got lucky!! I spray 200 shot and still no problems, When i bought them i bought bare, so i could get them checked and install good stuff in them, so they check out good @ the shop so we put manely valves and good springs fit for my cam and slapped them on and they are not to bad!
Dont get me wrong afrs, tflows, victors, the procomps are not and i take my hat of to the companys who make them great heads!!! but @ the time i could not afford them.
Good luck guys

[1979bruiser]

cool. what else is your set up (antyates) and what kinda hp or times do you get from your heads etc?