360 head trip

omahamoparguy said
I imagine the ssr is the short=side radius, ill assume that it is the short side going into the bowl from the floor of the port. sometimes know as the waterfall. I used to do some porting back in the day for a guy down in fl. Some tricks; widen the waterfall and have it very consistantly smoothed radius. Also, do not concentrate on the pushrod side of the valve guide boss too much. the other side produces swirl and turbulence and if you make each side, similar flowed troughs, they somewhat cancel each other out. widen the pushrod pinch as much as possible or actually install copper tubes in the guide holes and port the pinch 'til they expose the copper, stop there. (expoxie tubes in place). raise port opening as much as practible. shorten guide boss a bunch but leave the "tail" intact. 11/32 stem chevy valves, at .100 over length at exactly 2.00 diameter (1.94 work good in a 318 bore). pocket of bowl opening should be at 1.80- max diameter min. 1.75
with 2" valve. 3 angle valve jos with 45 degree seats. 5 angle if you can afford it.
later 360 heads have one "bad port" that you cannot make to match the others due to a bolt location creating a different shape to accomadate it. cant remember the earlier's X or J 'd design on this. as a rule of thumb with the small block, the bigger you go the better it will flow (within reason and keeping a few exceptions in mind).
you can get rid of the valve cover bolt boss that protrudes onto the port opening as long as you fill it up after (epoxy etc) and remember to use short bolts in that location.

Most of these are things I do, but when I go all out...I need to widen the csa more which means the push rod wall all the way to the bowl 'after the straight wall is maxed or maxed enough for me....the widening slows the air speed down, as does the roof raising which also gives a straighter shot at the bowl.
Yes indeed when it comes to big flow and sbm heads, bigger ports is where you end up.lol
*That one port you mention is the one with the lower/recessed head bolt boss, those I go through the casting just a hair, then use a 'press fit w/epoxy hardened washer to fill..then a grind off just a lil of washers edge that hang into the roof of the port.*
If you check out my other 410 thread there are pics of those heads and that port, if not Ill post some.

I will be doing the whole port, but I am going step by step for those who would want to try this themselves as maybe this will give them direction and idea of increases seen for each mod.