Benefits of Changing Cam Timing ??

[splicer]

505 cubic inches? She is out of air by 5100-5300 rpm. To get the best out of it I would try shifting no higher than 5500 rpm. What's it taching through the lights, 5400 rpm?

Here is the reality of the whole setup. The RPM head OOTB is only going to flow about 275 cfm at .546" lift (.570"-.024" lash).

I have tested a very mildly ported RPM head with flows of 290 cfm @ .600" lift. With an Edelbrock Torker II and a 1.56 venturi carb, that combination only flows 264 cfm @ .600" lift. With the Edelbrock RPM manifold, 251 cfm. The M1 single plane, 266 cfm. The Edelbrock Victor, 271 cfm.

There isn't enough air there, with 505 CI, to make any more power beyond 5300 rpm.

I appreciate your feedback and am sure that you're probably correct....I would like to know the math involved to relate engine displacement and head flow to RPM for my own edification...

I'm considering installing a Holley Street Dominator....Do you have any info on one of those ? ...and yes it's at 5400 thru the lights....

Thanks again to all
Splicer

 

[Cranky]

The HSD is a good intake but you are running 500 cubes! Imo, it's still not going to let it breathe like it should. I dunno, never ran one of those on anything that big....just saying.

 

[splicer]

The HSD is a good intake but you are running 500 cubes! Imo, it's still not going to let it breathe like it should. I dunno, never ran one of those on anything that big....just saying.

I got ya....it's supposed to be better than the Torker and almost as good as the Victor.....maybe a few hundreths there.....Pretty sure I'm almost maxed out on the heads like IQ52 says....
Splicer

 

[lewtot184]

something to think about; how much driveability do you want to give up for power? a bigger single carb and a victor intake will rob some torque below 3500rpm. with multi-carb you may be able to get your cake and eat it too.

 

[RustyRatRod]

Yall are arguin for nuthin. Ain't no benefits to changin a cam. Everybody knows that. What's the matter with yall?

 

[lewtot184]

:icon_lol:

Yall are arguin for nuthin. Ain't no benefits to changin a cam. Everybody knows that. What's the matter with yall?

we're all northerners and can't help it,..:icon_winkle:. o.k., .690 roller, ya'll happy.

 

[RustyRatRod]

:icon_lol:
we're all northerners and can't help it,..:icon_winkle:. o.k., .690 roller, ya'll happy.

Das wut I'm tawkin bowt.

 

[splicer]

A little update after a season of racing.......

With a little weight trimming(180 lbs) and some tweaking , car is now running 11.16 at 122 mph but I think limiting factor is still the heads and I'm trying to decide whether to go with Indy 440-1 head package and bigger cam or port the Edelbrocks (with bigger cam as well).... I want this car solidly into the 10's and still street legal...

I don't mean to imply it has to be docile on the street......snotty is fine , I'm not going cross country....lol

Any suggestions would be appreciated...

Splicer

s

 

[Supershafts]

You're trying to decide btwn edel and indy. You never should have went with the edel for that motor, and honestly get the bigger indy..

Here is an example i have 2 motors, both within 14" of each other and one the same c.i. as you, both use 6.3 rod, both with the indy's, one in the same 11 to 1 compression area the other is like 10.9, both using custom rollers in the high 280 and more then 600 lft, both are used on the street plenty, both use large custom built bg dominators, both big indy intakes, custom headers

Both will 1.5 off a flat punch and that's also skating thru the next 50', making a hard pass in 1st and 2nd only, and cruise out 3rd gear, you would have read my back window the entire time in that run as i went somewhere in the 10.9 to 11.10 area, cruising out 3rd makes it different all the time. Both cars are heavier than 3800, neither are using a 3.73.

The torker, holley sd and edel heads are killing you, that's for 383's and mild 440's.

 

[IQ52]

If you buy the 440-1 heads, you will have to get the ported ones to get them to flow better than the RPM heads to .500" lift.

It would depend upon your final goals which head would be the best to sink your money into.

We have ported the Edelbrock RPM heads into the 340 cfm range and have made 787 HP with a 451 stroker on pump gas. The ported 440-1 heads will make more power ultimately than the ported Edelbrocks, but if you already have the Edelbrocks and 750 or so horsepower is enough, just have the larger intakes and seats installed and have them ported. It costs less to work the Edelbrocks into that power range than to BUY 440-1 heads AND have them ported. The as cast 440-1 heads WILL NOT make the power of the well ported Edelbrock RPM unless the 440-1 heads are ported too. Then the 440-1 will make greater power than the RPM heads.

 

[splicer]

Thanks for your responses, Supershafts and IQ52.......750 to 800 hp would satisfy me but there are a couple of things that will influence what I do

1) I don't know of anyone in the Ontario area that can reliably do a porting job...

2) The eddies are the 88 cc chamber open chamber models...this might be hindering the engines performance now and might be worse with better breathing....

3) I miscalculated the compression ratio at 10.75 to 1 when I started this thread...It calculates properly to 10.3 to 1....maybe too low to make decent horsepower with current Eddy heads...can they be milled enough to correct this ??

Anyway, all of the above is shoving me towards the Indy package ....even given the large expense....

Any further comments are most welcome...

Splicer

 

[Supershafts]

You could order the heads from a trusted shop (IQ) done to what you want if none of the local builders can.

OR

Take a trip to the local track and find someone running in the low to high 9's, see what they have and who built it, ask some questions about there car and what parts they use, the Indy heads, or B-1 and which version, cars weight, gear, rpm, comp ratio .... stuff like that, you don't need the specifics like exact cam and stuff, you're looking to see someone near you has a 500" motor in the 700hp area and able to drive it and it's not 2400 lbs and has some stupid umpteen to 1 cr and WHO built it for them.

Now you have a shop locally to visit and feel out if you want to go there also.

Usually if the heads are right and the larger port Indy's or B-1s, playing in the 10.4 to 11.1 (flat pistons, and try and keep the piston dead 0 at deck, then you can adjust the quench) area with a roller in the 270@50 area and 650 to 750 lft area in the 106 to 108 cl you can expect to start at 720 plus with a single dom carb, make power right up to 7k and she'll start fairly low, really you should get it up into the high 700 low 800 area

 

[383man]

If you do go to Indy heads you could call Dwayne Porter as I got my Indy EZ heads from him. Great price and a good guy to deal with as he is one of the best head porters there is. I bought mine as he did some mild porting on my EZ heads and then shipped them to me. He is an Indy dealer so he can give you a good price. I stayed with the basic EZ head so I did not have to get offset rockers. If you want his phone # just let me know. My combo is something like yours as I built a 493 with the EZ heads and dished pistons for 10.6 comp as the EZ heads are 75cc's. I am using a solid flat tappet thats 264 & 270 @ .050 and about .590 lift but with my 1.6 rockers the lift is about .630. I run the Indy dual plane intake opened up tp Max Wedge size and I use a basic Holley 850 DP. I wanted what you did which is a car I can drive to the track and run 10's on pump thru the full exh and then drive home which it has run 10.70's so far. Good luck with yours and let me know if you would want Dwayne Porters # to talk with him. Ron