383 Engine rebuild

[BBodyBarrett]

i'm familiar with the 284/484 and it has it's place, but I think it's still a step too far. the 284/484 (the one I measured was actually 286/486) is ground on 108CL and will have about 72 degrees of overlap at the seat. of course a lot of this depends on what you plan to do with the car, race it or street cruiser. I think you'd be much happier with something like a comp cams 280/480 ground on 110CL; about 60 degrees of overlap. cams with higher overlaps aren't real happy with cast iron exhaust manifolds. my car was a '68 road runner 4spd car I bought new in '68. I specifically remember that the more I cammed the worse it ran; on the street and track. the best dual purpose cam I ran was a crower 201hj; no longer available. my car wasn't sloppy tuned. the engine just didn't like big duration with high overlap. even with some of the smaller performance cams your tuning abilities might be challenged with a 383.

I like the comp cams, they have some good choices. Thats probably what I will use. The machine shop is very good with Mopar engines, he is working up a cam / piston combination for the engine. I plan to use headers and a 3:91 gear. Thanks for the input

 

[BBodyBarrett]

We seem to be talking in circles. If the motor was truly rebuilt in 2002, it does not have stock pistons. Someone may have told you that it has stock pistons, but the truth is that it has similar to stock pistons, but they will not have the 1969 compression distance of 1.932". There were several stock like pistons available in 2002, and ALL of them had lower compression ratio than the 69 piston. Therefore, back to my original question, exactly what pistons are in it? If you want the motor to run as good as it can, and want to pick the best cam you must first understand what pistons are in it.

Or just fly cut the pistons and put it together the way you want. But, expect to get you butt whipped by minivans if you have a 7:1 CR 383 with the 509 cam.

In 2002 they honed the block and used the stock pistons with new rings, bearings, timing chain and a "Six Pack" cam, not sure of the specs. The machine shop builds a lot of Mopars, he is going to work up a cam piston combo after everything is cleaned and checked.

 

[BSB67]

In 2002 they honed the block and used the stock pistons with new rings, bearings, timing chain and a "Six Pack" cam, not sure of the specs. The machine shop builds a lot of Mopars, he is going to work up a cam piston combo after everything is cleaned and checked.

Got it. Great.

When he selects the piston for you, get the part number and let us know.

 

[lewtot184]

there's been mention of the 272/455 cam. I currently use one in my '69 r/t. on paper these cams seem a little anemic. the one I have measures [email protected]", [email protected]", [email protected]". I can say from experience that they can be over achievers with iron heads. I put a summit 6400 in a 383 4spd super bee a couple of years ago. it's a small cam but performs well. there's a lot of options and "small" ain't bad.

the real issue, no matter which cam, is piston to valve and retainer to guide clearance. the stock valve train will have about .100" of preload in the tappet. if the valve springs are floated from over revving, and everybody does it at sometime, the tappets will pump up and then there will be collision. usually it's a bent intake valve. large intake valves can make the matter worse. retainer to guide collision can actually cause a dropped valve which is catastrophic! aftermarket retainers reduce retainer to guide clearance, which isn't good. stock retainers won't work well with 1.50 and larger diameter springs. serious stuff to look at.

hope your engine guy is on his game with the valve train.

 

[Cojohnso1]

My mopar upgrade builds to deeper cam lifts and flat top pistons to 0 deck? I always assume the motor is now an interference motor. Serious over Rev or a timing chain mishap? Count on the valves getting tapped. In today's motors? Most stock builds are interference from the factory.

 

[lewtot184]

the old mopar performance bulletins used to always state that any cam with 284 degrees or more duration will likely need notched pistons. unfortunately this info is ignored. solid lifter cams with moderate lift and duration pretty much eliminate the problem. in my opinion hydraulic cams are the killer.

 

[lewtot184]

My mopar upgrade builds to deeper cam lifts and flat top pistons to 0 deck? I always assume the motor is now an interference motor. Serious over Rev or a timing chain mishap? Count on the valves getting tapped. In today's motors? Most stock builds are interference from the factory.

rev-limiter. good springs. reduce preload with hydraulic tappets.

 

[BSB67]

there's been mention of the 272/455 cam. I currently use one in my '69 r/t. on paper these cams seem a little anemic. the one I have measures [email protected]", [email protected]", [email protected]". I can say from experience that they can be over achievers with iron heads. I put a summit 6400 in a 383 4spd super bee a couple of years ago. it's a small cam but performs well. there's a lot of options and "small" ain't bad.

I've been in the 12.90s at 108+ mph with that cam with iron heads, exhaust manifolds, compression bent exhaust, 3.23, stock converter, and P235 BFG in a 4,250 car (race weight)

Over revving a 383 4 speed is like swearing, you don't plan on doing it, but it happens all the time. Mine, with just the MP 280/.474 sees 7000 regularly. Not that it should.

A reasonable lobe profile and lift, and zero preload would probably work on a 383 w/ no relief flat tops. But why?

Once you figure out your 906 volume, I bet that new Icon piston will be the way to go.

 

[lewtot184]

I've been in the 12.90s at 108+ mph with that cam with iron heads, exhaust manifolds, compression bent exhaust, 3.23, stock converter, and P235 BFG in a 4,250 car (race weight)

Over revving a 383 4 speed is like swearing, you don't plan on doing it, but it happens all the time. Mine, with just the MP 280/.474 sees 7000 regularly. Not that it should.

A reasonable lobe profile and lift, and zero preload would probably work on a 383 w/ no relief flat tops. But why?

Once you figure out your 906 volume, I bet that new Icon piston will be the way to go.

your experience is why I tried the 272. can't beat the facts!

 

[TetanusShot]

I've been in the 12.90s at 108+ mph with that cam with iron heads, exhaust manifolds, compression bent exhaust, 3.23, stock converter, and P235 BFG in a 4,250 car (race weight)

Over revving a 383 4 speed is like swearing, you don't plan on doing it, but it happens all the time. Mine, with just the MP 280/.474 sees 7000 regularly. Not that it should.

A reasonable lobe profile and lift, and zero preload would probably work on a 383 w/ no relief flat tops. But why?

Once you figure out your 906 volume, I bet that new Icon piston will be the way to go.

I've heard some pie-in-the-sky claims before, but that one is a little too incredible...

108 mph at 4250 lbs is like 425 wheel HP. With an optimistic 20% parasitic loss, you're making about 530 HP at the crank...

Iron heads, exhaust manifolds, restrictive exhaust system, 223 @ .050 & 455" lift...530 HP... No way. Are you sure it wasn't more like 13.90 @ 98mph? Or maybe your car actually weighed 3250 lbs?

As for the topic, I like Summit's K6401.

 

[lewtot184]

I've heard some pie-in-the-sky claims before, but that one is a little too incredible...

108 mph at 4250 lbs is like 425 wheel HP. With an optimistic 20% parasitic loss, you're making about 530 HP at the crank...

Iron heads, exhaust manifolds, restrictive exhaust system, 223 @ .050 & 455" lift...530 HP... No way. Are you sure it wasn't more like 13.90 @ 98mph? Or maybe your car actually weighed 3250 lbs?

As for the topic, I like Summit's K6401.

BSB67's numbers are real, but your horsepower estimates are off. i'm thinking 430+ at the crank. '67 charger; big car.

 

[fratzog lover]

there's been mention of the 272/455 cam. I currently use one in my '69 r/t. on paper these cams seem a little anemic. the one I have measures [email protected]", [email protected]", [email protected]". I can say from experience that they can be over achievers with iron heads.[/QUOTE

Be warned many publications still have this cam incorrectly listed as 231/231. It is not. But at 221/221, you still cant do much better for a genuine Mopar street/cruiser cam for your 383. And your valve train will thank you!

 

[BSB67]

I've heard some pie-in-the-sky claims before, but that one is a little too incredible...

108 mph at 4250 lbs is like 425 wheel HP. With an optimistic 20% parasitic loss, you're making about 530 HP at the crank...

Iron heads, exhaust manifolds, restrictive exhaust system, 223 @ .050 & 455" lift...530 HP... No way. Are you sure it wasn't more like 13.90 @ 98mph? Or maybe your car actually weighed 3250 lbs?

As for the topic, I like Summit's K6401.

More details are posted in the 13 second Section of Racers Hangout forum. I'll gladly answer any questions you have, and could post several et slips too if you like. I ran the car pretty regularly at a few different tracks, and have weighed it a few times. It started out over 4400 with everything including the A/C and pulled weight out over time. I did weight it at National Trail after a 12.961 at 107.05 run. It had a 1.976 sixty foot that run which was a lot better than the 2.05s at my local track. It weighed 4175 lbs that day without me in it, but included my helmet, two baby seats and 1/2 tank of gas. I actually have a professional picture of that run framed if you would like to see that.

 

[BSB67]

BSB67's numbers are real, but your horsepower estimates are off. i'm thinking 430+ at the crank. '67 charger; big car.

I think that's right Lew. If you use Mopar's Drag Strip Dyno, its like 420 or 430, and Moroso Calculator its like 405-415 hp. I suspect that the Moroso is probably more accurate, and certainly used more often. Of course these are both net flywheel uncorrected hp, not rear wheel. As you know Lew, we ran in some pretty decent air, so corrected to gross hp at std. conditions (typical engine dyno numbers) probably would not be a lot higher. Probably in the 430, maybe 440 hp range like you said.

 

[lewtot184]

I think that's right Lew. If you use Mopar's Drag Strip Dyno, its like 420 or 430, and Moroso Calculator its like 405-415 hp. I suspect that the Moroso is probably more accurate, and certainly used more often. Of course these are both net flywheel uncorrected hp, not rear wheel. As you know Lew, we ran in some pretty decent air, so corrected to gross hp at std. conditions (typical engine dyno numbers) probably would not be a lot higher. Probably in the 430, maybe 440 hp range like you said.

I still think about those days. this was back in the mid 1990's. what if we knew then what we know now, and what if we had the parts back then?

 

[BSB67]

I still think about those days. this was back in the mid 1990's. what if we knew then what we know now, and what if we had the parts back then?

No kidding. 1075 gram pistons w/ pins, 5/64 rings, compression bent exhaust, iron heads with stock valve sizes, hand drilling carb metering plates.........

 

[Don Frelier]

I'm still running the .455 cam in the Charger since 1997. It's about 32 years old now in the second engine. I have the original 66 block, KB hypereutectic pistons, 906 heads milled to 78 cc, weiand intake and 68/69 exhaust with h-pipe and 2-1/4" exhaust. I'm running MSD atomic and it's a wonderful thing.

 

[BSB67]

I've heard some pie-in-the-sky claims before, but that one is a little too incredible...

More details are posted in the 13 second Section of Racers Hangout forum. I'll gladly answer any questions you have, and could post several et slips too if you like.

No questions I guess.

 

[lewtot184]

No questions I guess.

I like pie!

 

[lewtot184]

No kidding. 1075 gram pistons w/ pins, 5/64 rings, compression bent exhaust, iron heads with stock valve sizes, hand drilling carb metering plates.........

i took off 3/4lb from the piston and rod of each cylinder in the 440 in my 65 dodge with modern parts. what do you think the effect of that would have been in 1995?