Purdy. Why didn't you go with the 235 heads?

 

The CC diameter is larger then 4.03 and I don't like that. Also for a 370 I don't feel the small advantage at high rpm is worth the loss of port velocity. I discussed this notion with many and that was the consensus with others as well.

 

Heads are raw, the timing cover is ...... damnit. I'll have to look and I'll let you know. I forget what color I used.

 

So far its looking like Ill be around a 7.625 pushrod. I am going to call Manton Monday and get a couple to test for diameter. I have all kinds of room on my exhaust valve, could run a 7/16 if I wanted. On the intake side the pushrod is offset in the hole a bit and much tighter. Based on my measurements a straight 3/8 should fit but it will be close. I think Ill try a straight 3/8 and a 3/8-11/32 taper from Manton and see. Ill just slap some bluing paste on them and see if there is any contact.

Johnson says lifter preload is .035 +/- .010, I am targeting +/- .005 since Manton can make anything I want. So far with a 7.625 length my range is .023-.042

 

Got some stuff coming from Manton. They were very nice to deal with, goal is to run 3/8 on the intake side and 7/16 on the exhaust side. I am gonna test out a few and see what will work.

 

Manton recommeded thick walled 11/32 all the way around on my tfs 225 heads. Worked great. Pulled it to 7900 rpm once by accident and the valvetrain was solid.

 

They suggest the above for mine. He wanted me to run as large as possible esp on the exhaust side.

 

They only make one thickness in 11/32 .120 I believe.

 

Why a larger pushrod on the exhaust? I would think the opposite for the increased mass of the larger intake valve but I suppose it could be that the exhaust valve is pushing against cylinder pressure upon initial opening. Is your exhaust lobe more aggressive than the intake? I presume same valve spring seat pressures and install heights on both intake and exhaust?

 

Spring pressures are the same.
Cam- 230/242 .617/.604 115+4

It's due to the high pressures on the exhaust valve with boost.