[Jay S]

The problem this will run into adding Rhoad’s lifters is the engine has a 2700 stall converter behind it, and original Rhoad’s and VPro both are both nearly pumped up by 2700. By 3500 they don’t gain any low end at all. They would gain a little bottom end at 2700, but not much. You would have to do a Vmax Rhoad’s and set the clearance higher to see much for low end power gains when the engine starts out at close to 3000 RPM, and even with a Vmax it won’t help that much at 2700, they are mostly pumped up, probably gain 20 lbs of tq at best. They would help drivability, if that was a concern. It doesn’t sound like that is a concern on this though.


There is still something wrong. I am not very surprised it is still struggling after the cam timing changing, 190 psi was enough before. A 350 can pump about 10 psi more than a 400 on the same octane. Probably even a little more, but even above 200 it could start having issues on anything less than 93 octane.

One thing obvious to most everyone that has chimed in, which have used stock 600 VAC Holley’s in the past ( I have done at least 10 of them), is that is a bottle neck for making much more than 300 HP. There could be multiple problems yet holding the combo back too, unknown problems in the short block, but that particular carb with no tuning is going to hinder any gains in performance in the future..

Could be the converter isn’t holding it either. The 200R4 should spin the tires hard coming out of first gear with its bigger ratio jump going into second. If it can’t do that, something could be wrong in the converter.

[ta man]

Originally Posted by Jay S

The problem this will run into adding Rhoad’s lifters is the engine has a 2700 stall converter behind it, and original Rhoad’s and VPro both are both nearly pumped up by 2700. By 3500 they don’t gain any low end at all. They would gain a little bottom end at 2700, but not much. You would have to do a Vmax Rhoad’s and set the clearance higher to see much for low end power gains when the engine starts out at close to 3000 RPM, and even with a Vmax it won’t help that much at 2700, they are mostly pumped up, probably gain 20 lbs of tq at best. They would help drivability, if that was a concern. It doesn’t sound like that is a concern on this though.


There is still something wrong. I am not very surprised it is still struggling after the cam timing changing, 190 psi was enough before. A 350 can pump about 10 psi more than a 400 on the same octane. Probably even a little more, but even above 200 it could start having issues on anything less than 93 octane.

One thing obvious to most everyone that has chimed in, which have used stock 600 VAC Holley’s in the past ( I have done at least 10 of them), is that is a bottle neck for making much more than 300 HP. There could be multiple problems yet holding the combo back too, unknown problems in the short block, but that particular carb with no tuning is going to hinder any gains in performance in the future..

Could be the converter isn’t holding it either. The 200R4 should spin the tires hard coming out of first gear with its bigger ratio jump going into second. If it can’t do that, something could be wrong in the converter.

I was going to respond as well with possible drive train issues..I've had bad transmissions that seem ok but have held power back. A fun day at the dragstrip would give us some data.

[Jay S]

I had an engine once that gained 10 mph in the 1/4 mile at the track from a converter swap. It went from 98 mph with a brand new 10” 3000 converter to 108 mph using a used 2200 OEM stall.

[Jay S]

We had an engine that was under performing and it turned out the stock heat range spark plugs were too hot. A worst case once a newly built engine would only idle until we changed to a colder plug. It can be a night and day difference. Just offering things to try.

[Jay S]

I was racing at the track in Kansas City on Wednesday nights when Jim Hand did the intake testing. I even lined up next to him a couple times.