I was going to install screw-in oil supply orfices (.080") just under the rocker arm shafts. This is unnecessary as custom Cometic head gaskets can be ordered with any size oil orfice you want in the gasket themselves making the screw-in orfices redundant.
With the dyno testing I got to do last year on a stock bore+.005 (347ci 3.922X3.59) with stock Apache heads. it picked up 10Hp with a slight bore notch on the exhaust side,with a 6.1 cam..........now this engine didn't pick up any hp with the Apaches over the Eagle heads before the valve notch it lost 15ft lbs of Tq , most likely due to the compression drop between the two heads.... all after the notch it picked up 10 Hp over the Eagles. but TQ didn't change much, it moved up 200 rpms in the band.
When I was building a 363(3.937X3.724), 1st cam was a 6.1 and it's HP&TQ #s were close to the the 347 HP/CI ratio, when I upped the cam to custom grind .610/.625,240/245@50 it made 660hp@ 6900 tore it down notched the bore re-ran it , it made 660hp@ 6900, both Hp#s were the average of 5 pulls each. with the angle these valves are at in the G3 , we don't have near the shrouding issues other engines have the G3 valves open away from the cylinder walls, not next to. even canted valve Engines like the BBC and Cleveland still open close to a cylinder wall and only travel slightly away from it. .............
next time you get a chance to look down an intake port of a G3 , notice how much of the valve you see.....Mmmmm gives me an Idea for a Video.
I've used Johnson Hylift on a lot of builds, only one issue, it was a manufactures defect, they made good on it. Crower I like but I suspect the are also made by Johnson. . Isky has 2 types one is a Repackage Johnson the other is also made by Johnson but has a sold bushing.....they are F--King expensive.
Howards had G3 lifters and now I have no idea what happened to them...the go to right now seems to be the New Hellcat(which is the new lifter across the board now) not many options for the G3
I have Johnson reverse flow in the new engine just built. I first bought the oem hellcat lifters which looked like standard oem lifters to me. Heard about the reverse flow Johnson lifters which look to me to be a higher quality lifter. There was a thread talking about them, but couldn't find it.
I have Johnson reverse flow in the new engine just built. I first bought the oem hellcat lifters which looked like standard oem lifters to me. Heard about the reverse flow Johnson lifters which look to me to be a higher quality lifter. There was a thread talking about them, but couldn't find it.
Some related issues concerning dwell/null times is the longer null times lend themselves to boost engines. Whereas shorter null times transition to drawing the charge into the cylinder quicker at higher speeds providing crisper throttle. This also allows cam timing to be optimized. However IMO this only becomes critical if you have a specific goal in mind and are optimizing the build. Cam timing is the important component in optimizing any engine utililizing as much lift as physical limitations allows. And of course when there are dependability considerations to consider the builder will have step back from the extremes as a further compromise to the build. In reality it can all be buit within reason and hp be made. I've even heard the common 4.050 stroker crank said to be a boost crank and the 4.080 crank for na.... look long enough and you can find most any theory.
The Higher RRs lend themselves very well to boost. back in the 70s the nascar thinking was 1.8+ for the super speed ways and 1.7 for the short tracks., stock SRT392 is 1.666, the Drag Pak 354's are using 6.30 C to C rods with 3.40 stroke for a 1.85 RR. Coyote is 1.623 RR and the interesting thisn is it has a bore to stroke ratio of .994 , it's an under square engine....20 years ago the experts would tell you that engine can't make HP because it's not over square....My how we have come long way in power production. My favorite Boost G3 is a 393 5.7 block build, 3.957 X 4.00 it's .989 B to S and 1.55 RR if you use a 6.2 C to C rod, the piston uses a 1.05 Pin height, it's on the smallish side but it's light enough that it won't stress rod too much at 8k.
the RR between the 4.05 and 4.08 crank is negligible with a 6.125 Rod , 4.05 is 1.51 and 4.08 is 1.50. Piston Velocity difference is 58 FPM at 6500 RPMs and 1 degree of crank rotation 4.05 @73* and 4.08 @ 74*. the difference in usable pin height is only .015 every little bit helps with cylinder pressures being much higher in a boosted application, but it's not enough to "chase after" if you already have your parts or are on a super tight budget. K1 4.08 cranks can be had for under $800 dollars and will support up to 1200hp boosted, vs Manely/Molnar $950-1400 price. granted you can go an extra 200hp with the better cranks, going to cost roughly the same amount to balance either of the rotating assemblies.
Side note....most people don't spin any of these builds high enough to utilize any of the advantages anyway.
Totally agree, the minute differences are minor as long as it is quality.
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