First time Porting.

[Runner71]

440
4spd, 3.91

Heads, 516 Closed chambered 79cc
Been running them all summer, car been doing great since i found the right tune for carb and ignition.

160 - 165psi across all 8 with .39" headgasket.
Car has alot off bottom torque wich was the purpose with the build ( My first ever )
Got bored and wanna learn new things so i figure, I wanna swap the headgasket to a .18" for some more cylinder pressure! ( Have valve clearence ) Lets port the heads? Been reading books /articals/ytube about it.

The plan of course is some more power. It's just a cruiser but hey i wanna get as much out of it as i can with the parts thats in it.

So i jumped on it, 19h later the first head is done i think?

Intake.

 

[Runner71]

Exhaust.

Mayby i opened up the exhaust to much? dont know. Ive just been going on feel and how the "flow" looks.
I know you don't wanna open up to much because the loss of velocity( low end toque) on low lift. but I figure I have could afford that so took some extra
Toughs, ideas, tips? Have i killed it already and need to look for new ones?

 

[PRHeads]

I’ve never seen a 452 head with a chamber like that.

That’s a lot of porting for a first attempt.
After opening up the bowls and pinch area a lot, like you have done ........one of the more critical areas of the port becomes the short side radius.
Unfortunately, that’s not something that can accurately be assessed by looking at pics.

A before/after flow test is what’s needed if you really want to know how worthwhile your porting efforts are.

Most people take too much out of the exhaust port.

This is a 346 head with the stock 1.74/2.08 valve sizes.
They flow around 220/155 ootb.

This one flowed 260/193.

 

[Badvert65]

It looks like you damaged the exhaust valve seat area in some pics. If you are lucky, lapping the valves will fix that. If not, machine shop will likely need to either recut or replace the seat. You'll typically get better results concentrating on the roof of the port, instead of the floor.
But it looks good, other than that.
jus sayin....

 

[Runner71]

Thats before i started the madness. They had alot of meat in them. The short sides I just cleaned off with 150grid.
I have most definitely lost some velocity on low lift or i think atleast. But the engine has alot off torque so i was thinking.If I open up a bit more on the inlet on the exhaust then mayby it will give some more flow at mid to high lift. Almost every flow test ive seen so far when porting for velocity( keeping the exhaust small ) Gives higher flow on low lift say .300 but you drop on the midrange instead. Well, guess time will tell if i had it all backwards Flowbench hmmm

 

[Runner71]

It looks like you damaged the exhaust valve seat area in some pics. If you are lucky, lapping the valves will fix that. If not, machine shop will likely need to either recut or replace the seat. You'll typically get better results concentrating on the roof of the port, instead of the floor.
But it looks good, other than that.
jus sayin....

Yupp been touching the seat here and there. Will see if lapping the valves fix it, otherwise that one is going to the machine shop. Gonna be more careful on the "gas" for the next one

Also the guides could have some more meat left one the next one

 

[PRHeads]

You’re saying that head has the casting number 4006452?

 

[Runner71]

You’re saying that head has the casting number 4006452?

Yes that's what im saying but I had to go check. And I mix them up with the 452's because of the harded seat's.
Casting is 2406516

 

[BSB67]

I say good for you. Unfortunately, you'll have a hard time deciphering what did help and how much.

So, how much did you cut the intake to head mating surfaces?

Any problem sealing the China wall/head/intake three-way corner?

 

[BSB67]

Yes that's what im saying but I had to go check. And I mix them up with the 452's because of the harded seat's.
Casting is 2406516

Oh, okay. You posted a minute before me. You can disregard my questions as they don't apply to the 516s

 

[PRHeads]

In case you haven’t seen these:

http://www.moparts.org/Tech/Archive/bb/62.html

http://www.moparts.org/Tech/Archive/bb/42.html

 

[Runner71]

I say good for you. Unfortunately, you'll have a hard time deciphering what did help and how much.

So, how much did you cut the intake to head mating surfaces?

Any problem sealing the China wall/head/intake three-way corner?

Ive gone from 14.65" to 15.40~" on the exhaust faceing the block. Funny thing is, I have the mopar porting templates but haven't used them, in mine mind i was just going for a little‍ Guess time will tell, But mayby i should have saved a bit more on the floor ramp side at exhaust. Have not had any problems with sealing.

 

[Runner71]

In case you haven’t seen these:

http://www.moparts.org/Tech/Archive/bb/62.html

http://www.moparts.org/Tech/Archive/bb/42.html

I will read! But the ship has sailed so to speak, Hopefully i havent messed them up to much - either way i have atleast make the other head similar and see how it works out

 

[69a100]

Better to cut to little than to go hog wild, you can always go back and touch up as needed. Are your hands still buzzin from doing the last head??? Mine rattled for 2 days after doing a /6 head.

 

[Runner71]

Better to cut to little than to go hog wild, you can always go back and touch up as needed. Are your hands still buzzin from doing the last head??? Mine rattled for 2 days after doing a /6 head.

cut to little, yeah that was the plan but then u get carried away, but it might work out well because of the torque cam. The buzz isn't that bad from yesterday/today i even prepared the other head. But then again im in the young 30's

 

[PRHeads]

As for the velocity/volume thing as it relates to street cars and torque/throttle response.......
My preference is to go after “the most for the least”.
The most flow improvement..... with the least amount of work, and the least gain in runner volume.
If you can flow more air through the same sized hole(port), the velocity actually goes up.
More flow, more velocity...... it’s a win-win.

So, with some well executed bowl work you can pick up 20-30cfm, at a readily accessible lift........ and only increase the runner volume by a few cc’s.
Here is a 452 head, 2.08/1.74 valves....... grind the seats, blended bowls and guide bosses........

Lift———I/E
.100— 67/54
.200—140/100
.300—208/135
.400—244/174
.450—249/183
.500—251/189
.550—252/191
.600—253/192



Here’s some numbers from a stock 452, stock valves, stock valve job:

Lift———I/E
.100— 61/59
.200—124/93
.300—185/123
.400—206/141
.450—215/144
.500—222/145
.550—226/144
.600—225/144

 

[Runner71]

Wow, im past that hours ago I had a pretty solid plan before i started the work but...whats the words, got carried away so to speak.
Well, it's nothing more then to finish the second head and try it out and see what's damaged been done. The throttle response was quite good untouched, hmm

 

[PRHeads]

I’ll be looking forward to the in car results!!

The flow from stock 516’s is pretty low, and the floor is quite flat, so the SSR isn’t as critical as a 915/906.
I’m sure you’ve picked up some flow.

 

[Runner71]

I’ll be looking forward to the in car results!!

The flow from stock 516’s is pretty low, and the floor is quite flat, so the SSR isn’t as critical as a 915/906.
I’m sure you’ve picked up some flow.

Hm okay so with some luck then this might work out. Gonna do some calls and see how far away a flowbench is, would be nice to compare stock to porteded. Then again it's cruiser with decent bottom power, dont really want a max hp 5800rpm street car on that rpm im at the brakes long time ago on the streets

 

[Runner71]

Also got a pair of 906's 1.74 on exhaust but its really nice with the harded seat's. Hate the smell with lead replacement for the gas..

Hmm, it's pretty crisp on the throttle.. or was .. Does it have something to do with the 1.60 exhaust of the 516 head?