1968 H Code 383 - 2020 Engine Refresh - Cam, lifters, pumps, etc.

[Gerald Morris]

You'd really like this cam in your 400! It should help quite a bit with that low compression the 400 would have. Just dont expect it to have a lopey idle...it will be smooth...at least it is in mine.

The 400 I build will NOT have obscenely low compression. I'm building it as much to 383 specs as possible, starting with a steel crank from a 383 shortblock I picked up for that very purpose. I'm looking for some closed quench heads, possibly 915's to go on instead of the open quench 452s I have at present. (I have 516s on my current 383, and they do their job nicely enough! Surprising isn't that?)

If I can build the 400 to something around 9:1 compression, that should do very nicely for our family needs. I hope to keep a nice 2 barrel carb on it, though NOT the Holley it came with. It was an RV motor to start with, and very likely has some RV cam in it now. But with those 452 heads, yes, its compression definitely is late-70s low.

I LIKE the 400 block! Extra ribbing, bigger crank bearing webs, larger water jacket ports for coolant flow; it was a wonderful block in the WRONG DECADE. But with the RIGHT sort of rebuild, it can be made a NICE motor. I don't plan on any obscene power output, but want optimum torque to turn the 2:76 742 open rear end I have. If I eventually can score a Sure Grip in the same highway gear ratio, we will be very happy. I might look into the new stuff toward that end.

These Lunati cams make strong contenders for the build. I also am considering a "purple shaft" from MP, but more modern stuff appeals....

 

[Luke Pokrajac]

The 400 I build will NOT have obscenely low compression. I'm building it as much to 383 specs as possible, starting with a steel crank from a 383 shortblock I picked up for that very purpose. I'm looking for some closed quench heads, possibly 915's to go on instead of the open quench 452s I have at present. (I have 516s on my current 383, and they do their job nicely enough! Surprising isn't that?)

If I can build the 400 to something around 9:1 compression, that should do very nicely for our family needs. I hope to keep a nice 2 barrel carb on it, though NOT the Holley it came with. It was an RV motor to start with, and very likely has some RV cam in it now. But with those 452 heads, yes, its compression definitely is late-70s low.

I LIKE the 400 block! Extra ribbing, bigger crank bearing webs, larger water jacket ports for coolant flow; it was a wonderful block in the WRONG DECADE. But with the RIGHT sort of rebuild, it can be made a NICE motor. I don't plan on any obscene power output, but want optimum torque to turn the 2:76 742 open rear end I have. If I eventually can score a Sure Grip in the same highway gear ratio, we will be very happy. I might look into the new stuff toward that end.

These Lunati cams make strong contenders for the build. I also am considering a "purple shaft" from MP, but more modern stuff appeals....

 

[Luke Pokrajac]

Sounds like a great application for the Lunati cam. Although Chrysler spec'd the HP 383 at 10:1 compression it's probably around 9:1. One way that I really can tell that the engine is producing a lot more torque is the ease in going from 1st gear to 3rd gear without the engine bogging. It pulls like crazy, even in 4th gear.

 

[Gerald Morris]

Sounds like a great application for the Lunati cam. Although Chrysler spec'd the HP 383 at 10:1 compression it's probably around 9:1. One way that I really can tell that the engine is producing a lot more torque is the ease in going from 1st gear to 3rd gear without the engine bogging. It pulls like crazy, even in 4th gear.

That 10:1 compression came w steel head gaskets and hi rise pistons on those 906 heads. I'm sure you're getting plenty torque too. How many RPM is your motor turning when upshifting? Open chambered heads produce higher torque along with power at higher rpm as a rule. Such was what they're designed for. What I plan for is high torque at LOW rpm; thus the desire for closed quench heads. The 915s came with larger valve bores in their second year. Mind you, the 516s were good for what they were MEANT for, but NOT for a high revving motor. For that, they need some work, which is better just to get different heads like the 915 to do.

I need to research the optimum head for low end torque combined with the appropriate cam to go with this. While I LIKE the 452 for the hardened valve seats and allowing flow at higher rpm, I don't think its optimal for low end work, despite the fact that it got drafted into this job by the corporate beancounters if not the engineers.

Perhaps some truck motor heads will suit? I must look into that. I hate spending $$ on stuff I can't then use!

 

[LocuMob]

Gerald, unless you're building a hot rod, 452's will do just fine. 915's can bring some decent money of you find them, so if they get too expensive you can end up spending close to a set of 440Source Stealth heads. I slapped a set of 452's on my 440 I build after the previous engine broke w connecting rod, and bent the Pistons in that cylinder. Same build minus the heads, stock bottom end, an Edelbrock Performer intake and carb, Purple Shaft .484 cam, and tti headers and full 3" exhaust. I noticed just a little drop off in oomph. Nothing serious, and the car moves out about the same.

The older cam is more of a drawback than the heads, I think. You really feel the engine come to life around 2500 rpm, it just wants to pull! A newer grind can get you the torque down low that you want. I'll keep the 452's on the 440 for as long as it runs.

 

[Luke Pokrajac]

That 10:1 compression came w steel head gaskets and hi rise pistons on those 906 heads. I'm sure you're getting plenty torque too. How many RPM is your motor turning when upshifting? Open chambered heads produce higher torque along with power at higher rpm as a rule. Such was what they're designed for. What I plan for is high torque at LOW rpm; thus the desire for closed quench heads. The 915s came with larger valve bores in their second year. Mind you, the 516s were good for what they were MEANT for, but NOT for a high revving motor. For that, they need some work, which is better just to get different heads like the 915 to do.

I generally shift between 1500 and 3000...sometimes upward of 3500. I wouldn't say that the new cam has changed my shift points but it does allow me to more easily skip gears.

I need to research the optimum head for low end torque combined with the appropriate cam to go with this. While I LIKE the 452 for the hardened valve seats and allowing flow at higher rpm, I don't think its optimal for low end work, despite the fact that it got drafted into this job by the corporate beancounters if not the engineers.

Perhaps some truck motor heads will suit? I must look into that. I hate spending $$ on stuff I can't then use!

 

[Luke Pokrajac]

Gerald, unless you're building a hot rod, 452's will do just fine. 915's can bring some decent money of you find them, so if they get too expensive you can end up spending close to a set of 440Source Stealth heads. I slapped a set of 452's on my 440 I build after the previous engine broke w connecting rod, and bent the Pistons in that cylinder. Same build minus the heads, stock bottom end, an Edelbrock Performer intake and carb, Purple Shaft .484 cam, and tti headers and full 3" exhaust. I noticed just a little drop off in oomph. Nothing serious, and the car moves out about the same.

The older cam is more of a drawback than the heads, I think. You really feel the engine come to life around 2500 rpm, it just wants to pull! A newer grind can get you the torque down low that you want. I'll keep the 452's on the 440 for as long as it runs.

I think the new grinds are better than the old purple shaft grinds...I liked the idea of going with something from the 21st century. Plus the Lunati Voodoo cams were designed by Harold Brookshire...one of the best cam designers ever. Before coming to Lunati he did all of the XE high energy cams for Comp.

 

[LocuMob]

I like my cam, but yeah, newer grinds give much better driveability and performance. I have an newer cam to throw in my Dart.