New Heads How much New power?

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junior

junior

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I just bought a set J heads from my builder fulley polished and ported bowl work and big valves and they have been milled conciderablly. I have an LA 360 bored 30 over but only 8.5 comp. builder tells me new heads will make it 10.1
1978 Volare approx. 3400lbs.
727 reverse manual
3200 stall
373 sure grip
eddy dual plane
650 double pump
headers 2.5 exhaust
510 purple shaft Last year car only ran a dissappointing 14.00 How much more power and et do you think i will pick up and was $500 a good price to pay for the increase
 
Hard to tell without knowing what heads are on it now. Need more cam info also. $500 seems like a good price if they everything is good to go and just bolt on.
 
Super hard to say without flow numbers to help guess.

Your car is heavy. With a low comp. engine and a big cam killing it, your ET was actually OK.
 
cam is 510 lift purple shaft the heads are the original j's intake I believe is the rpm. what were you saying about the rear gear to ???
The builder says with the new heads better flow more compression the cam is old school but should be a good fit I hope he is not just blowing smoke up my pipes he built my sons 408 and it runs very well
 
Not familiar with the 510 purple shaft. Is it hydraulic or solid? duration @ .50? Have a part #?
 
about 30hp and .2 tenths, with heads milled considerably - see if the intake bolts up without any gaskets, and do u have or are considering adjustable rockers or shorter pushrods and checking v to p clearance
 
Maybe the old tried and true .509/292? If the heads are milled and you pick up 1.5 pts of compression it should pick up with that cam. How much is hard to say. A friend of mine has a 68 dart with 360 and that cam, 456 gears with 28 inch slick and edelbrock heads untouched at 10-1 and runs 12.10's consistently, at close to your weight with driver. IMO it likes more gear though, 410 or deeper depending on tire size. May need to have your intake milled to fit also, depending on how much they took off the heads. Make sure to check piston to valve clearance also after installing them.
 
my pistons do not come all the way to the top p to v clearance should be good builder told me to use double intake gaskets on the sides and silicon for the ends my son told me more rear gear also but its a street car and see's limited track time if i see low 13s or with luck a high 12 i would be one happy camper
 
If the cam is installed at 108ish ICL, it's going to be lazy down low.

What was MPH on the run?

Does the converter really stall where advertised?
 
I'd say with what you have (considering all to be good), I would figure what is missing now. I ALWAYS tweak it to where it should be, and some, before trying to compensate for bigger and better. I agree that your car should run much better than a 14 flat. My opinion, should be in the 12's. Hunt like a mad man!! Check your full advance timing (I guess it should be between 38-44 degrees), check each cylinder compression, check for solid spark to each cylinder, Make sure your tach is correct and you will probably be shifting between 5800-6000 rpm's. Don't overlook the easy stuff, like is your throttle coming all the way open when it's floored?? Is the engine/fuel lines running cool, because heat is a killer. How about Jetting???
 
junior said:
my pistons do not come all the way to the top p to v clearance should be good builder told me to use double intake gaskets on the sides and silicon for the ends my son told me more rear gear also but its a street car and see's limited track time if i see low 13s or with luck a high 12 i would be one happy camper
Click to expand...

If the heads were milled considerably as you mentioned, then the there is no way you can double stack the intake gaskets. Depending on how much they were milled you will either have to run thinner than stock gaskets or possibly have the intake manifold milled to get it down far enough to bolt on and seal to the heads.
 
Do you mean the .509 cam another old and outdated design much better cams out there..
 
junior said:
I just bought a set J heads from my builder fulley polished and ported bowl work and big valves and they have been milled conciderablly. I have an LA 360 bored 30 over but only 8.5 comp. builder tells me new heads will make it 10.1
1978 Volare approx. 3400lbs.
727 reverse manual
3200 stall
373 sure grip
eddy dual plane
650 double pump
headers 2.5 exhaust
510 purple shaft Last year car only ran a dissappointing 14.00 How much more power and et do you think i will pick up and was $500 a good price to pay for the increase
Click to expand...

I ran 12.599 @ 108 mph with a F body and 360 10 years back--very similar combo. I had a 3.91 gear my J heads and a .484" Purpleshaft. \\

How much will you gain? I hate to be a Debbie downer but it could range from -50 hp to + 100 hp. No real way of knowing. Talk to your guy you got the heads from. J.Rob
 
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