valley firearms

Hello everyone. New to the mustang scene again. I'm on my 6th stang in 22 years. I sold my 65 fastback with shelby conversion in 88 for $2000. It's been 17 years and just purchased a 68 coupe to hotrod. The motor is very strong and very fresh. Only 500 miles on rebuild. The guy purchased stuff from Summit including the heads and 570 Holley Street Avenger. The card was impressively responsive with the RV cam it had. It ran like a top. But, being me, I couldn't leave well enough alone. I love a big cam! It is a hydraulic Comp Cam. The lift is .512 and the duration at .050 is 230. Of course I had to install gear drive as well. After install it fired right up and broke in without overheating or any other problems. It's been almost 20 years since I swaped cams in a mustang and it was still a breeze. I wouldn't say it's like riding a bike though. I adjusted the valves according to their sheet. I have not touched them since. I have driven the 68 about 100 after the install and it runs great. BUT, it doesn't want to idle in gear. It sounds like an awesome cam should in park but I can't tweak things enough to get it to idle in gear. I figure I should probably adjust the valves soon just to be on the safe side. It's kinda hard to hear the lifters with gear drive. I have lost some low end torque but figure I will gain that back with a 2500 stall converter. The 570 Holley is still very responsive in park and driving. I just feel it could do better with a bigger carb. This is my question. Do I have enough cfm's with the 570? It has been a long time since I have tinkered with cars and that is the first thing that came to mind after the install. I need at least a 650 to get better performance and to keep it idling. Please feel free to chime in. A little more background on the engine that may help. The heads are cast iron FMS stamped GT40P. Shorty headers and brand new dual exhaust. Edelbrock performer intake with the Holley 570 Street Avenger. The cylinders are bored .040 over. My transmission is an automatic C4. Any advice is appreciated. Love the site!

southernfordman

What size is the engine?

southernfordman

It sounds more like a the valves because my friend just adjusted his vavles and when he puts it in gears it dies.

valley firearms

Sorry guys, it is a 302

southernfordman

That 570 cfm carb should be plenty. I got a 600 cfm on my 351C and it runs great.

valley firearms

I wonder if it's just a valve adjustment needed. Does your 351 have a big lift cam? Mine runs great but doesn't want to idle.

valley firearms

When I adjusted the valves, the sheet said zero lash was when you feel a slight resistence when spinning the pushrods. Then give it a 1/2 turn. I read on this site and others zero lash was when the pushrod will not spin.

southernfordman

When I bought my car the guy side it had a cam but, he did not know what size. It sounds no higher than a 500 tho.

6mustang6

Do you have a larger torque convertor installed? My impala did the same thing after we installed a larger cam.

valley firearms

Not other than stock torque conv as of now. Plan on using a 2500 stall. With winter coming and no garage, it will probably have to wait until next spring.