413 engine lazy

[andyswed]

Hi.
I posted half a year ago about my 65 new yorker engine. its now back assembled whit new 0.40 pistons rebuilt rods whit arp bolts.decked and new cam bearing.
I was planning on using my old 516 heads whit 2.14 1.81 valves,but a small never the less hole   when porting came up in a intake port 
I then bought a pair of 452 heads and did a bowl job. radius seats an stock dimension valve (ferrea).i did get a 9.3 comp value ,a little low but still usable in my opinion.
I have the lunati 60303 and performer rpm intake,hp headers.dual 2.5 inch exhaust.
I dialed the cam in to 1 degree advance.
The ting is its still lazy under 2.500 rpm. I have a 2400 conv in so it should be a bit better than it is.
right now i have a holley 750 whit vaacum sec.  would a bigger or mec secundaries be better ?
after 2500-2800 it comes alive 
Have overcammed it ? should i go for smaller or another cam ? I would like the torque a bit lower down .maybe go roller hydraulic ?
Any suggestions is welcome .

Thanks from Andyswede.

[cudabob496]

I would discuss your setup with Lunati. You may not have enough compression ratio or cylinder pressure for down in the low rpms, given
the cam duration/lift.


From Holley:

QUESTION How do I know if a vacuum or mechanical carburetor is best for me?
ANSWER For street cars the vacuum secondary carburetor works best on midweight or heavyweight cars with an automatic transmission. They are more forgiving than a Double Pumper is because they work by sensing engine load. The mechanical secondary carburetor is best on a lighter car with radical camshaft and a lower gear and manual transmission or on a car that is going to be used for racing purposes.

[cudabob496]

May also benefit from a change in timing curve. May want more timing to come in sooner?

That converter sounds good, but do you have pretty high rear gears also? The rear gears,
the cam, and the converter should all be well matched.

[Chryco Psycho]

The Cam should be a good choice , the carb may limit top end power but is not hurting the low end .
Timing & tunoing would be the first call usually a lot there to work with , not sure what you did with the porting but it is easy to screw things up & go the wrong way & hurt flow / velocity , it sounds like you went big if you put a hole in the closed chamber heads . Do a compression test find out what you really have .
Switching to a roller cam would help , it will widen the powerband & increase drivability & response but it will cost $2000 or so to do the swap & their really seems to be fixable issues with the build to try first without throwing huge $ at it .

[cudabob496]

The Cam should be a good choice , the carb may limit top end power but is not hurting the low end .
Timing & tunoing would be the first call usually a lot there to work with , not sure what you did with the porting but it is easy to screw things up & go the wrong way & hurt flow / velocity , it sounds like you went big if you put a hole in the closed chamber heads . Do a compression test find out what you really have .
Switching to a roller cam would help , it will widen the powerband & increase drivability & response but it will cost $2000 or so to do the swap & their really seems to be fixable issues with the build to try first without throwing huge $ at it .

Ya, was thinking the same thing, that larger ports might be decreasing intake charge velocity, but I didn't get the impression
there was much porting done.

[andyswed]

Hi again.
Thanks for your answers.
Today i changed the carb to my old eddy 750, and it was a new car. Still a bit lazy,but i need to tune more. I now have a little ping at high rpm at 34 *  timing full mech advance. But i think it needs a bit more fuel so i will continue tuning.the advace is full around 2200 ,i dont use vaacum. And i will go up to 98 octane to.
I have 3.23 in the rear whit low profile tires, about 2700 rpm and 55 mph. Maybe a bit  low?
Was thinking about 3.73 later on.
the ting is that when it starts mowing the old c-body realy push away  .
I really like it .
My brother has a 65 chevy whit a good 350 in it and he was so longfaced today when i passed him 
I will do as chryco suggested and meassure comp.
I did go a little big on the 516 head whit a hole in it but not that big. Maybe i post a picture later.,but all other intake port are good.
I figured it was a bad casting..
The 452 heads i have now is only blended,short side and a little bowl job whit radius seat.
Thanks again and i will keep tuning, still have that evil galaxie 64 around waiting for me
Andyswede..

[andyswed]

And i am thinking seriously about going to a roller , did get a offer from crower, dont remember the specs now but it was around 1000 dollars for a set whit hydraulic lifter,cam and push rods. I think the springs was there to.
What do you think about the crower cams ?

[cudabob496]

And i am thinking seriously about going to a roller , did get a offer from crower, dont remember the specs now but it was around 1000 dollars for a set whit hydraulic lifter,cam and push rods. I think the springs was there to.
What do you think about the crower cams ?

Have a Crower solid roller in my 496 for 12 years. Been great! Just make sure the duration matches your cylinder pressure, or you can lose power.

[Chryco Psycho]

Crower is great , they have good Mopar grinds available , lifters are $35 each , new pushrods $200 , new dist drive & fuel pump pushrod $150 , new valve springs $350 , cam $400 , cam button $40 , maybe new retainers $100 . So yes $1000 is a good deal if you get springs included .
 I would go back to the Holley & tune that , if the eddy carb is better the Holley is waaay off but at least you found part of the issue

[cudabob496]

ya, don't wanna spend $1000 when it could be a $20 fix!

[andyswed]

I will tune the holley later on,the eddy carb is my old one but i did the swap just to see what happened.
Been looking at a proform, looks nice and a good price,. Should i go vaccum or mech ? I kind of like mechanic ports .. thinking 850 cfm ..

[cudabob496]

I will tune the holley later on,the eddy carb is my old one but i did the swap just to see what happened.
Been looking at a proform, looks nice and a good price,. Should i go vaccum or mech ? I kind of like mechanic ports .. thinking 850 cfm ..

From Holley:

QUESTION How do I know if a vacuum or mechanical carburetor is best for me?
ANSWER For street cars the vacuum secondary carburetor works best on midweight or heavyweight cars with an automatic transmission. They are more forgiving than a Double Pumper is because they work by sensing engine load. The mechanical secondary carburetor is best on a lighter car with radical camshaft and a lower gear and manual transmission or on a car that is going to be used for racing purposes.