Schubeck roller lifters, stroker HP estimate

[ramcharger]

OK, thinkin' way ahead to my next engine build after a pot 'o' java :drinkers:
Well seasoned '74 360 LA block (I already have it and it's never been bored) align honed, decked so pistons sit .005" in the hole. Eagle forged stroker crank, Eagle H beam rods, main studs and stud girdle from Hughes Engines. The rotating assembly will be internally balanced. HV Melling oil pump with a custom oil pickup and pan from Moroso. Custom forged pistons from JE or Diamond with the dish matching the combustion chambers on the large valve HD Magnum heads from Hughes engines with a set and measured CR of 11 to 1 and a quench height of .045". Heads will be fully ported locally. I plan on 10 degree locks and valve retainers too. Cam will be the Comp Cams Xtreme Energy 20-742-9 solid mechanical roller with 236 @ .050 duration and .564/.570 lift and Schubeck roller lifters. Probably run a Jessel belt drive too. Topping it all off will be either a Edelbrock air gap or a yet to be determined single plane with a 750 or 850 double pumper, as intake manifold selection is limited with the magnum heads. This will be going into a A-body with a 3000 stall 727 and 4.10 gears that will be used for bracket racing and occasional street usage. The car will most likely have an electric vacuum pump for the power brakes and I have a high tolerance for nasty cams on a street car. Oh yeah, also plan on large doses of N20 with an adjustable kit from NOS, and yes, I will be using a 140 gph electric fuel pump with 1/2 braided line from stem to stern with a bypass style regulator and a fuel cell. Now for the questions:
1. Anyone heard good or bad regarding the durability of Schubeck Roller X Lifters on the street and track? Are there any other roller lifters out there that can survive some street use? I chose these lifters as I do not want to be picking tiny roller bearing out my engine every 6 months and have heard a lot of horror stories.
2. Anyone got a dyno program that would give a HP estimate? I may back half this car if HP is much over 450.
3. Has anyone heard of rocker stud and or boss failures with the cast iron magnum heads and high spring pressures? Comp Cams recomended springs for this cam run 385# open
4. Any suggestons on rocker arms that can withstand this kind of abuse?
5. Anyone see anything wrong with this combo and have suggestions?

 

[moper]

There's really only a couple of things I can see. First, head choice..I'd look to either MP big port Commandos, or the Edelbrock RPM Magnum heads. Factory Magnum heads even with decent porting IMO just cant move the air well enough to do any more than 475hp in most cases. They flow very well for street type engines, but with NOS and a solid roller, I dont think they will be the best fit for this build. I would also run a single plane if you plan the NOS use. It will be easier to tune with a single plane (better distribution for every hole and larger plenum to help bend/turn the air). An M1 would be a nice medium sized piece. The carb needs to be at least 800cfm, and a DP version. The studs in the Magnum heads should be fine. They arent my best subject, but I believe they all use screw in studs, and they will hold those specs easy. Also, you can use Chevy rockers for less $$, and get a variety of ratios. BTW, Magnums use 1.6 rockers, so the cam will be bigger feeling if it was spec'd for LA engines. That is a small roller, if you are concerned with flat tappet loss, you may want to consider using a Magnum block to start with, so you can just use the hyd roller setup the factory does...It's four figures cheaper than the path you're looking at, but will make slightly less power (that's what the NOS is for, right?lol). In terms of solid rollers, Schubecks have no failures I know of, but I havent ever used them, and the guys that I know did (only a couple really), dont use thier cars on the street. Comp has that new Endurex solid roller, that has an EDM oiling hole in them to help keep those stupid needles in place..And the light profile and spring pressures (for a roller) should mean even the std solid rollers should live for a while. The ones that come apart usually are running a lot more pressure, and are not street profiles. Also, in terms of saftey while running the solid rollers..You may want to bush the lifter bores. I wont run any roller besides factory without bushing them. That eliminates any side-effect lower end damage should a lifter/pushrod/rocker/spring fail. It also stabilizes oil pressure bleeding out past worn or O/S liffter bores. Also, you'll want to make sure the Schubecks you go with allow pushrod oiling..The Magnums use that too. On the Jesel, that looks cool, and makes cam timing cahnges easy, but you sure you want that? A decent roller chain and tensioner can get very similar performance results for much less. But it doesnt dampen harmonics or let you switch cam phase without pulling the timing cover. In terms of HP, a recent dyno session (not tuning, just stuck the car on the rollers):

418 (340 + .040 and 4" MP crank) running a .520 lift 220 @ .050 solid flat tappet cam, 1.5 Cranes, Edelbrock LA heads (mild port cleanup), 10.8:1 quench dished Ross pistons, Edelbrock Performer RPM (not air gap), a 3310 730 carb, and 1 5/8 headers with flowmasters, 727A, 8 3/4.

It makes 450HP at 5300, 510TQ at 3400. Pump gas, idles at 16" vaccum. With a larger cam, larger intake and carb, and better headers, it would very easilly clear 500hp, and move the torque peak up 1K rpm. It's actually hard to drive, because the torque curve is so flat, it will tear up the Hoosier QT Pros at any speed under 50mph, in any gear. He is now re-stalling (lowering)the convertor, and raising the gear ratio to make it more drivable.

In your case, with good machining, and good heads, it should be well over the 450 mark. Closer to 525 depending on the heads used, and with the NOS, you are seriously stressing the factory block. (I use 600 hp as the limit for factory small block builds) If you can afford the parts to run that power level, you can afford the $2200 new block. Really, the girdle, the caps, the studs, the bushing of the lifters, and the rest of the quality machining will run more than $2500 anyway, and it's still thin cylinder walls and 2 bolt mains. Also, with the factory block, and NOS use, I'd rethink the Eagle forged crank deal...A Callies is a beter part, that wont flex and stress the mains as much. You can spend now, or spend later. My $.02 anyway...Definately sounds fun in any case...lol.

 

[ramcharger]

You're right about the heads, I think I'll go with the Econo W-2 cast iron heads and have them ported, they should have 300cfm capabilty, mopar and Indy both offer single planes for this combo. I checked the Schubeck web site and their Mopar lifters do offer pushrod oiling as well as offset pushrod seats, but I won't be needing pushrod oiling with the W-2s. Man, those lifters are pricey! I think I'll go with the Comp Cams EDM Lifters you had suggested. As far as blocks are concerned, I checked the MP catalog and they do not offer a non-siamese, 4 bolt main block with 59 degree tappet angles. They do offer a HD 340 block but I do not know if it has 4 bolt mains at this time.

 

[70Barracuda]

Don at FBO has a roller E headed 340 with all the goodies, Calies, Racer Brown roller, think it has a M1 on it too makes just under 500 for $5,000
Killer deal
Those Schubeck lifters are well worth the coin. They have saved 2 engines that I know of by stopping valve float.

 

[perfacar]

hello, just curious, how does schubeck lifters stop valve float? doesn't the valve spring control that?