[Stu1]

Before switching to my 406, I wanted to see if changing from a 1.5 RR to a 1.6 RR would make any difference in performance (butt dyno). Engine is a 355, 10:1 with reworked 601 heads and a Crane 212/218 Z cam (FT). Big difference so far just on the intakes, torque increase is very noticable off idle on up. Also see more vacuum at idle and cruise, same route to work each day so I have a good feel for the car. Rockers are SS Ebay units, 120 buck shipped. I am VERY pleased with the bump, I thought it might be a slight delta but it's more than that. I guess getting the valves off the seats faster was what the setup wanted, sort of like a quasi-roller profile. Will try the exhausts next, but I wanted to share this in case anyone wondered if it was worthwhile. On my setup, definitely. Yes, the engine needs a bigger roller cam but this was quite a bit easier and faster to do. Having been snakebit from too much cam, I picked this small one to see how it would work on my daily driver. I am slowly getting better at cam selection, leaning on Desktop Dyno but I don't do enough builds these days to really nail the selection.

 

[shovelrick]

Are your springs good with the extra lift?

 

[jeff swisher]

I built many 601 heads and a buddy stuck 1.6 rockers on both sides of a set I did for him.
Ran 135 seat and 330 over the nose [email protected] .050 cam and then add another 2 degrees for the 1.6 rockers.
Lift was .571" with 1.6 rockers then take another .026" off for lash.

Ran super hard in that 3000 lb truck with 355" to the tune of 11.50's
Had 11.5" vacuum at idle.. plenty for power brakes.
His heads got the 1.94-1.60 valves and screw in studs and guide plates.

Those 601 heads do not back up or stall on flow as far as I have had tested.

 

[billdini]

I looked at those rockers on Ebay, Jeg's and other stores but was worried about durability and went with 1.5 Scorpions but I have a hotter L79 cam. Usually SBC's like more exhaust then intake although I always run a single pattern cam. That is a fairly small cam as you noted and have increased both lift and duration with 1.6 which should lower your idle vacuum but hey seat in the pants is what I go by. I suspect you will see another increase in HP (not vacuum) when you do the exhaust. Did you go from a stamped steel rocker? Will be curious how well the low cost roller rockers work out for you.

 

[jeff swisher]

First sentence was 1.5 RR to 1.6 RR
Roller vs Roller.

 

[billdini]

First sentence was 1.5 RR to 1.6 RR
Roller vs Roller.

Jeff I am to old to talk in acronyms. I had to look up Rich L79 SEG on his face comment today. Thanks

 

[Stu1]

I looked at those rockers on Ebay, Jeg's and other stores but was worried about durability and went with 1.5 Scorpions but I have a hotter L79 cam. Usually SBC's like more exhaust then intake although I always run a single pattern cam. That is a fairly small cam as you noted and have increased both lift and duration with 1.6 which should lower your idle vacuum but hey seat in the pants is what I go by. I suspect you will see another increase in HP (not vacuum) when you do the exhaust. Did you go from a stamped steel rocker? Will be curious how well the low cost roller rockers work out for you.

Switched from Summit branded aluminum 1.5 RR. The Ebay units are stainless, they are not as nicely finished as the higher priced versions but are working fine. Idle vacuum is HIGHER with the 1.6s, did not expect that but it might be related to gas column velocity being higher with the faster rate. I will probably switch the exhausts this weekend as I'm stoked with the results. I had an L-79 cam prior to this, it was not that great for my gearing and the 350TH but was decent with the blower I ran later. Anyway I see so much BS being posted about rocker swaps that I figured I would just try it and then give some real actual results for the members. Well worth cost and minimal effort IMO...

 

[billdini]

Switched from Summit branded aluminum 1.5 RR. The Ebay units are stainless, they are not as nicely finished as the higher priced versions but are working fine. Idle vacuum is HIGHER with the 1.6s, did not expect that but it might be related to gas column velocity being higher with the faster rate. I will probably switch the exhausts this weekend as I'm stoked with the results. I had an L-79 cam prior to this, it was not that great for my gearing and the 350TH but was decent with the blower I ran later. Anyway I see so much BS being posted about rocker swaps that I figured I would just try it and then give some real actual results for the members. Well worth cost and minimal effort IMO...

I asked because I saw RR thinking Rocker Ratio. I am constantly looking up acronyms these days. I am running the L79 cam in my L79 with 11 to 1 CR. See I can do it too In my case that cam is perfect and can go down to 1000 rpm in 4th and up a hill and accelerate with no problems. I used the Howard version of the L79 in the wife's 350 71 Camaro that I could tell was not going to be great. However I lost two lobes pretty quickly so it didn't matter anyway and testing was minimal. The stock TH350 converter wasn't gonna cut it for sure when I pulled it back in the garage. I originally wanted the HC FT 217/225 but it was backordered as was everything else coming out of Covid. I am currently waiting and waiting for the HC roller cam version of that which will probably be close to yours with the 1.5 RR. Boy these acronyms are fun.... In any case I just didn't want to take a chance with cheaper RR and went with Scorpion after I once lost a Comp Cams roller tip (one side fell out) on my roller 230 duration cam in my Z28 at startup.

 

[Stu1]

I asked because I saw RR thinking Rocker Ratio. I am constantly looking up acronyms these days. I am running the L79 cam in my L79 with 11 to 1 CR. See I can do it too In my case that cam is perfect and can go down to 1000 rpm in 4th and up a hill and accelerate with no problems. I used the Howard version of the L79 in the wife's 350 71 Camaro that I could tell was not going to be great. However I lost two lobes pretty quickly so it didn't matter anyway and testing was minimal. The stock TH350 converter wasn't gonna cut it for sure when I pulled it back in the garage. I originally wanted the HC FT 217/225 but it was backordered as was everything else coming out of Covid. I am currently waiting and waiting for the HC roller cam version of that which will probably be close to yours with the 1.5 RR. Boy these acronyms are fun.... In any case I just didn't want to take a chance with cheaper RR and went with Scorpion after I once lost a Comp Cams roller tip (one side fell out) on my roller 230 duration cam in my Z28 at startup.

I have a Lunati Voodoo 217/227 roller for the 406 build, I'm converting over to roller everything going forward. i had so much legacy FT parts around it took a while to burn through the stock. I have one more BBC build that I may use the last boxed cam I have, it's a mild truck app so i it might be OK esp. with 1.8 rockers. BTW I was not happy with the L79 blueprint cam, it's something GM did for 4 speed/4.11/11:1 combos that aren't too daily driver friendly. Has those long ago and got tired of the gas mileage and noise.

 

[billdini]

I have a Lunati Voodoo 217/227 roller for the 406 build, I'm converting over to roller everything going forward. i had so much legacy FT parts around it took a while to burn through the stock. I have one more BBC build that I may use the last boxed cam I have, it's a mild truck app so i it might be OK esp. with 1.8 rockers. BTW I was not happy with the L79 blueprint cam, it's something GM did for 4 speed/4.11/11:1 combos that aren't too daily driver friendly. Has those long ago and got tired of the gas mileage and noise.

I don’t like the standard L79 M21 and 12 bolt 3.31 combo but I love that cam. It is designed for 11 to 1 cr that my original has but I also used it in a few 350’s with 10 to 1. I get over 18 mpg average too but I wouldn’t expect much with your rear gears