help with a Mopar cam

[danbud61]

Hi!

I have a 1971 340 block, J heads with stock double spring.
I purchased a purple cam ( advance dur 268/272 dur @50% 228/231 lift 450/455).
Can anyone tell me what push rod size I should be using?

 

[rumblefish360]

Thread moved, pay attention to the catogoires. (Spelllling!!!!!!)
Welcome aboard and your answer is dependent of the amount of head/block milling that was done as well as gasket thickness to a degree.

Otherwise, if nothing else was done to the engine, stock pushrods will do fine even if the new head gasket is .020 thicker.

 

[danbud61]

10 mill on both the heads and block.

Stock mopar gasket set

 

[danbud61]

Hi!

I have a 1971 340 block, J heads with stock double spring.
I purchased a purple cam ( advance dur 268/272 dur @50% 228/231 lift 450/455). part # P4452761
Block was decked 10mil
heads where also shaved 10mil
Can anyone tell me what push rod size (length) I should be using?

 

[mopar340dave]

You need to go through the procedure to check it out for yourself...here's a link. The first instructions I wrote are for LA small blocks (engines with factory shaft mounted rockers). The second set of instructions is for the Magnum motors (individual rockers). The procedure is essentially the same with different hardware involved.

http://www.forabodiesonly.com/mopar/showthread.php?t=52803

Follow the instructions that I posted on there. You will need at least 1 adjustable checker pushrod. 2 makes it quicker and easier.

Dave

P.S. A quality 5/16's push-rod will work fine for your application.

 

[mopar340dave]

If yours needs a 7.5" pushrod, here's a killer deal!
http://cgi.ebay.com/ebaymotors/Part....c0.m245&_trkparms=72:543|65:12|39:1|240:1318

 

[danbud61]

Thanks for the link, that was a great deal.

 

[mopar340dave]

Just do yourself a favor and check the pushrod length before buying. It's very important. The wrong length will cause parts to fail.

 

[rumblefish360]

Your good to go with the stock pushrods. Minus .020 is acceptable for the stock lifters to handle. The thicker Fel-Pro would have been ace's @ .039.

 

[danbud61]

Thanks for the info gents!

 

[mopar340dave]

I agree with Rumblefish360 in that it should be ok, but I would still go ahead and check the length. That way, you can buy the optimal pushrod length for your motor. The manufacturing tolerances from the production line were a little loose to say the least.