Chamge to Ti intakes and 50 degree seats?

[gregsdart]

Dave B, i had the rev limiter set at 8,000, and when it didn't shift it just quit pulling because of the rev limiter, not the motor. Most motors built with the heads i run have peak horsepower at 7000 to 7200 and generally are 572 cubic inch in size. So seeing peak horsepower at 7600 rpm on the dyno was a bit of a surprise. The heads only flow about 400 cfm at .800 lift, so they are a limiting factor, being basically a revamped version of a max wedge head first designed in the early 1960s..
Other comments about not making the horsepower it showed on the dyno do not take into consideration all the factors involved, like the failed shift, soft low rpm launch. These run numbers came IN SPITE of all that, and it being day one with this combo. Only two runs were made.
Had i figured out what was holding up the 1/2 shift from occuring, how much faster would the car be , accelerating at max power at about 80 feet off the line for that full half second it was hung up at 8,000 rpm against a rev limiter? We will learn in the spring. I fully expect BIR tech to tell me i am too fast for my 8.50 cert, and by a bunch.

[gregsdart]

On the Ti valves, since more than a few people have pointed out a possible lack of improvement, i think the smart move is to run the car as it is, see if it is fast enough to justify the upgrade to 7.50 cert, or just short shift it to stay at 8.50 or higher.

[Dave B]

i would never tell anyone to not take weight out of their valve area. I have a manley stainless and a tit 2.300 valve here. 146 grams compared to 99 grams. But i dont see it making big strides in what you stated. Keeping your valve springs in good shape with tit will be better. We had old dart 360 headed bbc with stainless valves. It would run up to about 8100 and float valves. That is nothing to have happen either. It does your valve job and lifters no favors. Good luck getting it sorted out. It doesnt take much to cert a car at 7.50. Get her done and see what it will run.

[Rick!]

Ok, cool, so the rest of the story is that you input an incorrect shift setting with a new bullet.
Found your combo, nice set of parts.

[gregsdart]

Rick! No, the cause was a move from the MSD I had providing ground to my airshifter solenoid to using the Deadenbear box shift light circuit. I did not understand the lockout setting in the box also held up that circuit till the setting ran out. As far as i understood it, that lockout circuit was only supposed to safeguard the transbrake circuit.

[gregsdart]

Dave B, at 74 years old i don't race a lot. Maybe fifty runs next season if all goes well? So justifying a change to Ti valves isn't easy on a budget. The Pac triple springs i run have been very reliable, long life IMHO, so if the lifters and rockers hold up well, I hope to only need to check lash often. With a 10.72 deck height mopar and these heads, you have ten inch long pushrods, 7/16 heavy wall. At least i bought the tapered ones to help a little on weight.

[KnightEngines]

How about just a change to 50 deg seats & a little more port work by someone that really knows what they're doing?

[gregsdart]

Knight engines, that is on my mind. A move to a 2.35 intake from the 2.30 i currently run would also be considered. I must admit i know very little about all of the ways a move like that would affect power output. So my hope is to find somwone that has had positive results with my particular head castings, enough to justify the move.

[KnightEngines]

With the lift you have 50 deg seats are a no brainer, just changing the seats alone and a simple blend in would be an easy 20hp.
Rework the ports to suit and it'll go up from there.

Usually you can just reface the 45 deg valves to 50 deg & add a 38 deg backcut - depending on how much margin they have.

Sometimes with steeper seats a larger valve is not a good idea - the casting may not support the significantly larger throat required by steeper seats and larger valves, or the port volume may not be able to be made large enough to support the throat size - or any other number of variables.
Best to find someone familiar with the castings before committing to anything.

But a switch to 50 deg seats on the existing valve size is a safe bet.

[ClassAct]

Greg, as big and long as your valves are they should be Ti. Those heavy, clunky SS valves have no business in an engine like yours.

And I do 50 degree seats on most everything regardless of lift. Proven it many times on the dyno and at the track.

[mt-engines]

Greg, as big and long as your valves are they should be Ti. Those heavy, clunky SS valves have no business in an engine like yours.

And I do 50 degree seats on most everything regardless of lift. Proven it many times on the dyno and at the track.

When going to a 50 degree seat, the throat percentage normally increases.. thats where the power comes from. But then again pulling harder on a port too small can be a disadvantage.

I run 2.350 stainless valves in 8000rpm big block chevies all the time. Just keep an eye on your springs.

I've run 2.400 stainless valves in drag engines at 8300rpm.. its not the end of the world. The lighter valve won't make more power unless the underhead shape changes.

I do think if he wants new valves, just go to the 2.350 titanium, those heads can make some serious power with a bigger valve. Hes at that rpm to where it will pick him up in power. But he will need a bit of port work to pick it up substantially. But his chassis has more in it to run quicker.

To the OP, if you ever saw the Mirada at BIR, we spun that Big block mopar 8500 every pass, and would change springs every 3 years or about 300-400 passes even though they checked good.. RPM was never an issue. The Orange Dart in Outlaw we spin 9200-9600 depending on blower overdrive or timing. And that gets springs every 3 years. Dont be afraid of rpm, this isn't the 60s anymore.

[ClassAct]

Greg, as big and long as your valves are they should be Ti. Those heavy, clunky SS valves have no business in an engine like yours.

And I do 50 degree seats on most everything regardless of lift. Proven it many times on the dyno and at the track.

When going to a 50 degree seat, the throat percentage normally increases.. thats where the power comes from. But then again pulling harder on a port too small can be a disadvantage.

I run 2.350 stainless valves in 8000rpm big block chevies all the time. Just keep an eye on your springs.

I've run 2.400 stainless valves in drag engines at 8300rpm.. its not the end of the world. The lighter valve won't make more power unless the underhead shape changes.

I do think if he wants new valves, just go to the 2.350 titanium, those heads can make some serious power with a bigger valve. Hes at that rpm to where it will pick him up in power. But he will need a bit of port work to pick it up substantially. But his chassis has more in it to run quicker.

To the OP, if you ever saw the Mirada at BIR, we spun that Big block mopar 8500 every pass, and would change springs every 3 years or about 300-400 passes even though they checked good.. RPM was never an issue. The Orange Dart in Outlaw we spin 9200-9600 depending on blower overdrive or timing. And that gets springs every 3 years. Dont be afraid of rpm, this isn't the 60s anymore.

This post should be a sticky

[Rick!]

Manley 2.35 stainless intakes in 440-1s modified to emulate 572-13s will last a bit over 1000 laps before the head of the valve cracks. This is with an Isky solid roller with .460/.450 cam lift using 1.7 rockers at 7-7200rpm and a World block at 572 cid. BTDT, didn't get the prize.
For the OP, that's about 20 years worth of laps or one Sick Week... Ti valves do add barstool hp so there is that.