Hello,

I just picked up a dart with a /6 and it has the stock '72 unhardend (i guess) valve seat head on it.

Will I run in to pinging if i put a milled (.060 or a little more) head on there with oversized MP valves on it with the stock cam/carb/exst?

Will the stock cam be cool with the melling "340" springs on the head?

I have this head just chillin in my garage and would be nice to get a little more torq out of the slant.

No, no it will not ping. The big valves / milled head with all stock engine are not the best bang for buck -investment. Of course when they are there, you can add the other things later.

I got some 0.5 seconds off with the good valve job with oversize valves in my super six'd engine. In the stock engine the most restrictive thing will be the 1 bbl carb. I'll recommend you to swap it at least to 2 bbl.

By the way. I got some pinging problems with the original 1 3/4 " exhaust when I did the carb swap and the engine start to breath at speeds over 4000 rpm.

Tight valve springs will not help at all in a stock 1 bbl engine. I have stock replacement slant six springs from Comp Cams. They work well at 5500 rpm, no need to go any harder ones.

Long time no see CrAlt

Asssuming the head has not been milled before, .060 should only bring your slant to the 9:1 Comp range, so pinging shouldn't be a problem, as long as you do not have too much mech advance.

You won't get much benefit from larger valves with the stock ports, IMO you would be better off spending money on porting than O/S valves.

Get a supersix intake/carb in place of the 1 bbl, and open up the exhaust.

I have no idea on the 340 springs on a stock cam.

-S/6

This is a zero-buck upgrade

I /have/ the ported,os valve, 340 spring head in my garage. Has about 4K miles on it.

So I just need to figger out if the spings will hurt the cam..

Im going for MILAGE on this car.. I figger a little more CR would help things.

Seeing that you have the head ready to go, swap it on, it will run a little better.
The 340 valve springs won't hurt the stock cam.
As already noted, the 1 bbl carb will be the restriction, followed by the exhaust system so focus on getting a bigger exhaust system and carb when you have a chance.
DD

If I remember correctly, according to official Chrysler literature, the Slant 6 engines received hardened valve seats starting in 1972, yes 1972!

Hmm..i'll have to pull the rocker shaft and stick a strait edge on there and see if the valves are sinking.

Im not looking to make the car any quicker. Just a smoooooooth running, quiet milage getter.