Port match worth the effort?

TheSwede · Feb 20, 2015

Got a set of 516 and a torker intake that is far from perfect when it comes to port match, is it worth the time to make them match or shall I leave it as it is?
Power gain 10-15 hp?

383 with a 284H

66Satellite47 · Feb 20, 2015

Port matching is definitely worth the minimal effort if you have the die grinder & proper carbide bit. Match the gasket, being sure to bolt up the intake first, & use a bent coat hanger to see & feel the areas to grind. Lots more power is available by opening the area under the valve seats, "pocket porting". Start with small changes while being VERY CAREFUL.

Propwash · Feb 20, 2015

66Satellite47 said:
Port matching is definitely worth the minimal effort if you have the die grinder & proper carbide bit. Match the gasket, being sure to bolt up the intake first, & use a bent coat hanger to see & feel the areas to grind. Lots more power is available by opening the area under the valve seats, "pocket porting". Start with small changes while being VERY CAREFUL.

X2!! Removing any metal opens up more CFM, thus more flow, volume and less resistance. That equals power. After the experience with my past couple engine builds, learning from some pretty smart folks here, other sites and experienced engine builders, it's come to reality pretty quick that how well and how much fuel flows through the intake, into the heads and down through the valves should be the building block to base the rest of your engine off of.

Coyoteduster · Feb 20, 2015

Absolutely worth the time and effort! A flow bench will make a believer out of you ...

Meep-Meep · Feb 20, 2015

From what I know the roof and sides are probably the most important areas to match but really should ask IQ52 since he has a flow bench. 10-15 HP? Maybe at max RPM but not counting on it.

Cranky · Feb 20, 2015

Think of steps. Easy to fall down them than it is to go up them. If the port mismatch is going down a step, that's not nearly as bad as the fuel/air charge trying to flow up over a step. And air is more forgiving than the fuel is. Bad ports will make the fuel charge want to separate out of the air stream. Do the heads have any port work done to them? The bowl just under the valve is pretty crappy from the factory and it needs attention if you want any kind of an increase in performance from them. If you port match without at least working on the bowls, you probably won't see much improvement if any.

TheSwede · Feb 23, 2015

Thanks for all the help, I spent a couple of hours working on the heads, damn it was a dirty job!

Cranky · Feb 23, 2015

Yup...grinding or machining on cast iron is a dirty job. Need to have good ventilation when working on the stuff.

66Satellite47 · Feb 23, 2015

I forgot to ask, what size valves in the 516's? I ported a couple sets of those for friends with real god results. They used stock 2.08/1.74 hp size at the time.

TheSwede · Feb 23, 2015

66Satellite47 said:
I forgot to ask, what size valves in the 516's? I ported a couple sets of those for friends with real god results. They used stock 2.08/1.74 hp size at the time.

My 516 has the 2.08/1.74 setup, pretty tight in the guides too, will just grind in the cleaned valves, throw in new seals and put them back together.
The previous owner did some kind of restoration of the engine but it needed some minor adjustments, for example put the pistons in the right direction on no 2 and 8 cyl....
And of course clean all threads and lube them with copper grease, some of the exhaust manifolds bolts where so stucked they broke of so I had to drill them out.

One more question, I will mill the block straight, will I need to put shims under the rocker arm axles? How do I measure preload on the lifters?

Port match worth the effort?

TheSwede

Well-Known Member

66Satellite47

Well-Known Member

Propwash

Well-Known Member

Coyoteduster

Well-Known Member

Meep-Meep

дворянин

Cranky

Banned Henchman #27

TheSwede

Well-Known Member

Cranky

Banned Henchman #27

66Satellite47

Well-Known Member

TheSwede

Well-Known Member

Similar threads