ZZ383 Fast Burn Heads/Cam/ValveTrain...

[L31MaxExpress]

With a dyno sheet in hand the torque peak/curve would have been evident. If the cam in there peaked 3.5k which would be near perfect for what you're doing and the new peaks at 4.5k you just went the wrong direction for your gearing and your main concern that seems to be towing.

If you factor drivetrain losses for the chassis dyno it wasn't doing terrible for a mild 383.

You can raise the peak and still get more torque in that rpm range. Better headflow generally adds more torque everywhere. A bigger cam often adds torque everywhere beyond the extreme low-end as well.

I like Rhoads variable lifters for this very reason. You can go up a couple of steps in cam and get the low end torque and driveability of the smaller cam but around 3,500-4,000 where the lifters restored to full duration and lift you get the increased power of the larger cam. Rhoads lifters also increase the idle and no load vacuum substantially. My 11:1 383 with 210cc ports has a 218/228 @ 0.050, 110 LSA, .578 lift cam. At 650 rpm it makes 19 in/hg vacuum. At 3,000 rpm with no load it makes 24 in/hg. Throttle response is quick and it has a rapid torque increase just off-idle. Torque peaks is more of a plateau than a peak and it stays within a few ft/lbs of peak from 2,500-4,500 and makes peak hp at 5,700 rpm.

I would love to see a before and after dyno chart.

 

[Hipster]

You can raise the peak and still get more torque in that rpm range. Better headflow generally adds more torque everywhere. A bigger cam often adds torque everywhere beyond the extreme low-end as well.

I like Rhoads variable lifters for this very reason. You can go up a couple of steps in cam and get the low end torque and driveability of the smaller cam but around 3,500-4,000 where the lifters restored to full duration and lift you get the increased power of the larger cam. Rhoads lifters also increase the idle and no load vacuum substantially. My 11:1 383 with 210cc ports has a 218/228 @ 0.050, 110 LSA, .578 lift cam. At 650 rpm it makes 19 in/hg vacuum. At 3,000 rpm with no load it makes 24 in/hg. Throttle response is quick and it has a rapid torque increase just off-idle. Torque peaks is more of a plateau than a peak and it stays within a few ft/lbs of peak from 2,500-4,500 and makes peak hp at 5,700 rpm.

I would love to see a before and after dyno chart.

I have used rhoads as well and they do calm down a cam.

Sheets would be nice.

 

[L31MaxExpress]

I have used rhoads as well and they do calm down a cam.

Sheets would be nice.

I have used them on several builds myself. They worked even better on the cammed L30 305 in my Tahoe than they did on the 383. Tahoe gained 4 in/hg of vacuum, a noticeable amount of torque off-idle through the midrange and pulled more smoothly through the entire rpm band. Gained about 2 mpg over standard lifters with that setup as well.

 

[Wheeler]

I’m using the Edelbrock Performer RPM intake I believe they call it.

yes I agree that I don’t want my rpm band to move to much, but also agree that I can make more hp/tq through out the entire range by stepping up. IF I’m not happy with it, I keep the heads & change the cam. I know my torque converter was set up stock. It’s NO good for what I have & want. At a red light light idle is like 500rpm+ wanting to almost die. I upped the idle & caused dieseling... so I have to bump the stall up to maybe 2400...

I want more power/torque.. learning as I go...

Truck works “good” but not what I “want” if ya know what I mean.. I read about all these guys with 383s making x amount of power & torque.. works soo good yada yada.. well I’ve been behind the wheel of 500rwhp cars & various other nice rigs.. mine just seems sluggish... nothing $$ won’t eventually fix!!!

 

[Wheeler]

Well here we go.. he’s had issues. Had to change weights & springs in the new MSD Distributor, replaced vacuum advance as it wasn’t working, 650cfm carb too small, went to 750.. he’s still not done, but here was a pass... 275rwhp & 330rwtq at 3k. So the power curve moved down 500rpm.. BUT I never increased any tq.. which I find odd. He told me it’s like a totally different truck driving now. He still has some tuning to the carb to finish off. Has lean tip in he wants to richen up..we will see.. it looks very promising!!!!

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[L31MaxExpress]

Well here we go.. he’s had issues. Had to change weights & springs in the new MSD Distributor, replaced vacuum advance as it wasn’t working, 650cfm carb too small, went to 750.. he’s still not done, but here was a pass... 275rwhp & 330rwtq at 3k. So the power curve moved down 500rpm.. BUT I never increased any tq.. which I find odd. He told me it’s like a totally different truck driving now. He still has some tuning to the carb to finish off. Has lean tip in he wants to richen up..we will see.. it looks very promising!!!!

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Output seems a little low but how it goes down the road is not peak hp or torque number alone. Low end torque should only increase when the lean stumble is corrected. I would expect the hp to continue rising well above 3,000 rpm. Did you end up using the ZZ383s Fastburn heads and cam?

 

[Wheeler]

Output seems a little low but how it goes down the road is not peak hp or torque number alone. Low end torque should only increase when the lean stumble is corrected. I would expect the hp to continue rising well above 3,000 rpm. Did you end up using the ZZ383s Fastburn heads and cam?

Yes Fasburn Heads, but ZZ4 Cam, TCS 2200rpm Stall converter. I agree 100% numbers mean nothing.. how it goes down road & pulls camper will be the real deal.

IF for what ever reason I’m not happy, I may look at a custom grind cam from Isky

 

[L31MaxExpress]

Yes Fasburn Heads, but ZZ4 Cam, TCS 2200rpm Stall converter. I agree 100% numbers mean nothing.. how it goes down road & pulls camper will be the real deal.

IF for what ever reason I’m not happy, I may look at a custom grind cam from Isky

Did he ever get it finished up? What do you think of it?

 

[Wheeler]

Won’t have er until next week when I get home from work. But I will post back of what I think ect...

 

[Wheeler]

Had er out today. Hooked up camper as well. 5K (dry) down highway at 110km/hr (65mph) 3100rpm in 3rd locked up. Pulled great. IF I laid into er she would go.. trans temp 160. 2 small carb hiccups leaving a stop sign. I hit er & she stumbled a tad. I’ll talk to him on that. Un hooked works good. Do I expect more? YES.. he said if I’m not happy he will change the cam for free. I may take him up on that offer.....