Trickflow A460 360

Where are these heads designed to operate? With a 2.4 stainless valve what's a safe RPM range? what kind of power could be made with safe RPMs in a 540-572ci and a 1x4 tunnel ram? This will be in a mud drag truck with short runs. 3-7 seconds.

ill take a stab ......... 1075 -1100 , 7600-7800 rpm

I'd be content( for a little while) with a smooth 1k. My main concern was the intake valve. That thing has got to be heavy.

How about 7000-7200 rpm max give or take a Little depending on spring pressure and cam profile.

My choice would be 2x4's on that intake or a 1x4 on a single 4 intake.

If you are building this engine from scratch, get as many cubes as you can. ie 598 or 604, because torque is your friend in the mud. HP is part of the equation, but more torque almost always wins.

It wont be an unlimited budget deal, so billet stuff is out of the question. I'm thinking an A460 block with scat 4340 crank and rods. 4.5 maybe 4.6 crank. I may change my mind before I get closer but as of right now I hate to buy a block and bore it 4.6 right from the crate. So is the general consensus the 2.4 intake valve weight not a big deal around 7k? I'm under the impression a P51 headed engine will need to be a lot more high strong to make the same power as these A heads? I have P51 heads now, I'll be selling for the A heads if they are a better match.

The guy that I bought my engine from had SS 2.450 valves in it, and it did fine. Valve spring life goes down real fast with weight and speed. The faster the r's and the heavier the valve the less the spring life is. So if you use those valves and keep the r's down around 7k they are going to last longer than if you spin it up higher. I can't say exactly how long the springs are going to last, but be aware that it should be part of the maintenance on the engine to check them regularly with a quality tester. If you go to a Ti valve, it will make the springs last longer, and be a better investment in the long run, but not necessary.

As far as punching out a new block to 4.6" there is no down side to doing it. A lot of new blocks are punched out that far and the life is still plenty long. If you screw up a hole, it can always be sleeved. My other A block has a sleeve in it because there was a small pit found in the bore after it was opened up to 4.6", and the sleeves are stonger than the block material.

if i remember right, that casting is set up for a 5/16 stem intake valve which will lighten it up some.

My 557 on pumpgas made 906@6900 w 2.35 stainless valves.
I wish id bought them instead of the p51s the first time since I already needed pistons and a manifold anyways....

mr.horsepower wrote:if i remember right, that casting is set up for a 5/16 stem intake valve which will lighten it up some.

A set that I recently purchased did come with 5/16" intakes.
I can agree that many of the engines using the new A heads with normal cams and such...will make good power at 6800...7000.

I can attest to the stainless exhaust valves contacting pistons at 9,000 RPM....resulting from a broken ring and pinion and a forgotten high side chip...
Keith

Wheelie58 wrote:

mr.horsepower wrote:if i remember right, that casting is set up for a 5/16 stem intake valve which will lighten it up some.

A set that I recently purchased did come with 5/16" intakes.
I can agree that many of the engines using the new A heads with normal cams and such...will make good power at 6800...7000.

I can attest to the stainless exhaust valves contacting pistons at 9,000 RPM....resulting from a broken ring and pinion and a forgotten high side chip...
Keith

Ouch. That could happen to anyone.

I can attest to 9k for the majority of a eight mile pass and wouldn't recommend it. Didn't hurt anything,but probly had a horseshoe up my butt. 7 to 7500 I wouldn't have a problem with given the right springs and maintenance.