Hi!

I wanted to port match a set of 340/360 heads.

These are some later 360 heads 4448308

How much can I enlarge the exh ports without ruining the heads?

I am paying a 340 exh gasket on them and the difference is huge! How much grinding can I get away with?

one more...

Top & sides only is what i do, dont think the floor will gain much but the short turn is horrible so try to make it better.

suggestions on how to make the short turn better?

Do I risk hitting any water jackets? Places to watch out for thin spots? How much can I poen them up all around? 0.060"?

Thanks!

and how can larger can I make the ports all around? How much is safe?

DO NOT port match the bottom 1/3 of the runner. It may even decrease flow.

Any port matching will be worthless unless you open up the valve bowl. That's the choke point.

On the exhaust side you want to leave the port a little smaller than the gasket and then make the header or exhaust manifold slightly larger than the gasket to give you a step to reduce reversion. But don't touch the bottom of the port window!

Look up articles about porting LA heads on the internet. There is a wealth of information out there, some of it true.

R.

You can go all the way to the gasket line but theres no reason to do it on the 1,3,2,4 cyl cause that will be a huge amount to remove, besides all flow gains will be up in the lifts where your intake port are already done.
Most flow will be in the bowls.
And while your at it melt some old piston to plug the heat crossover

Google porting small block mopar heads and you can find some real interesting reading.

thanks!

You need to raise the floor not make the hole bigger

Don't enlarge the exhaust port at the exit, at all.
The later the head casting, the better..........
(894, 915, 587, 974, 596, 051, 308)

Short turn is non-exsistant on early heads. The best
you can do is "roll" as big of a radius on it as possible
off the seat. Don't cut EGR bumps out of the floor
but, if they are drilled, plug them. (late heads)

What head porter is best known for obtaining the most power potential out of a factory set of small block heads? This video is very impressive! Does anyone know the details on this paticular combination? 644 hp with modified stock heads, intake, carb, exhaust manifolds while running the factory air cleaner assembly...that is AWESOME!

http://www.youtube.com/watch?v=I1gswAFxcBc

Anyone?

Thanks for the compliment, I ported the heads and intake, Scott Koffel did the valve job and final blend to the seat. The motor is apart at the moment and as a matter of fact I am making a slight change to the intake short turn.

On the exhaust gasket match, the 308 exhaust has a really nice short turn and port shape in general. I would do a clean-up on the runner. Raise it to the gasket and widen it just to clean up. After cleaning up the short turn dont make it any lower just to match a gasket(I would not go all the way to the gasket shown on the width, especially the shared wall of the two center ports, but I dont think you would hit water).

Thanks for the feedback. Are you running a 800cfm thermoquad and is that the current set-up in your Duster?

Not an 800 on mine but I did the 800CFM carb on Brian Wilseys car and he's gone 11:20's with it on polyglass tires.

What kind of flow numbers do you see out of your ported heads? Have you ran that motor in your Duster yet? Sorry for all the questions. lol