383 cam selection mistake??

[4speed68rt]

Looks like it should be a real strong mid to upper rpm motor. One of those that you are always keeping the rpms up to get good throttle response. Make sure the valve springs can handle the lift. I'd say good for racing, not so much for cruising and doing burn outs. haha

 

[Geoff 2]

Post #10.

You do NOT plan on xx degrees initial timing. The engine combo, & particularly cam duration & overlap, will dictate what the optimum timing at idle is. Be prepared for more than 20*.....

 

[Runcharger]

TM6 and headers should match, convertor may be a bit light and it would probably prefer 4.10's If it was me I'd run it though.
I remember about 30 years ago a friend of mine put a 383 together in my shop. He ground the crap out of the heads with no plan whatsoever, big headers, big convertor and put in way too big of a camshaft. According to everything we read it was going to be the slowest 68 Charger ever. It was a real dog, only ran low 12's. All the experts said it would be 14's at best.

 

[rkohlman2013]

For the one that is in the motor with 155-160 psi?

No idea, i didnt rebuild it.

 

[rkohlman2013]

Post #10.

You do NOT plan on xx degrees initial timing. The engine combo, & particularly cam duration & overlap, will dictate what the optimum timing at idle is. Be prepared for more than 20*.....

yeah it was a general first thought of how much it would take looking at the numbers..

 

[rkohlman2013]

yeah it was a general first thought of how much it would take looking at the numbers..

Well guess the good thing is the box was damaged from Jegs and missing half the cam kit so I am shipping it back and getting a refund. A guy that live about a 1/2 away brought it to me this evening saying it was in his driveway. Called Jegs, customer service looked at delivery pictures of an open cam kit in a driveway. At least the delivery service takes photos of there crappy work.

So any recommendations?

 

[RemCharger]

TM6 and headers should match, convertor may be a bit light and it would probably prefer 4.10's If it was me I'd run it though.
I remember about 30 years ago a friend of mine put a 383 together in my shop. He ground the crap out of the heads with no plan whatsoever, big headers, big convertor and put in way too big of a camshaft. According to everything we read it was going to be the slowest 68 Charger ever. It was a real dog, only ran low 12's. All the experts said it would be 14's at best.

My daughter runs my 383 Polara with a TM6 - .509- 3.91, hefty converter and runs mid 12s.
They aren't inherent torque monsters.

 

[rkohlman2013]

My daughter runs my 383 Polara with a TM6 - .509- 3.91, hefty converter and runs mid 12s.
They aren't inherent

Do you know what cam is in it pumping 155-160?

We have a Lunati 704 in a 383, 2600 stall and 3.55s. The 703 and 702 have similar power bands 703’s power comes in a little later, from more overlap, and makes more power.

this weekend I am going to pull the front cover and timing set to see if there is a grind number or anything on the camshaft I can see. The previous owner said it had a cam in it. it idles pretty smooth and pulls good vacuum at idle, like 15-17. I was going to do a cam kit in it for a little more aggressive cam, ordered a Lunati but sent it back because the box was open, missing half the cam kit, and was dirty like the fedex guy took it off-roading. Hughes engines are out of hydraulic cams, thought about a MP cam but read the mixed reviews about quality.

 

[Outsider]

Too bad you don't know how far down in the hole the pistons are from the prior owner's work. You say the present cam is mild, it has 915 closed chm heads, and it only has 160 cranking comp? Seems low for a closed chm head mild cam; hope the pistons aren't way down in the hole like truck pistons.

One of mine with KB fltp pistons .025" down in the hole has a 245 deg @ .050 installed a few deg adv with a big lope, open chm heads and I have about the same cranking comp as you presently. Another one I have with old TRWs about 0 deck has 230 deg @ .050 installed a few deg adv with very little lope, open chm heads and I have about 190 cranking comp.

So if your cam is presently like a stock magnum cam @ 220 deg @ .050 and you go to a bigger cam makes me wonder how low your cranking comp and lack of bottom end pop will be. I like the idea of pulling a head and measuring pist to deck, it would sure be nice before you buy a cam. PS: I do like the Lunati cams.

 

[Geoff 2]

I have used a few Isky cams in engine builds over the last 4-5 yrs. All are performing well, no flat lobes, buuuuuuuuuuuuuuuuuut I used re-faced factory lifters to avoid lifter/lobe failure. Any lifter stock or aftermarket, that is 25+ yrs old will be a good lifter to have re-faced.
Isky cams are a bit more expensive & hopefully that s because they use as better quality cam core.
For your engine, I would use the 270 Mega.
It is veeeeeeeeeeeery easy to over-cam a short stroke engine that will be used on the street & convert it to dog status. I would also lose the TM6 intake & use a dual plane intake.

 

[rkohlman2013]

Too bad you don't know how far down in the hole the pistons are from the prior owner's work. You say the present cam is mild, it has 915 closed chm heads, and it only has 160 cranking comp? Seems low for a closed chm head mild cam; hope the pistons aren't way down in the hole like truck pistons.

One of mine with KB fltp pistons .025" down in the hole has a 245 deg @ .050 installed a few deg adv with a big lope, open chm heads and I have about the same cranking comp as you presently. Another one I have with old TRWs about 0 deck has 230 deg @ .050 installed a few deg adv with very little lope, open chm heads and I have about 190 cranking comp.

So if your cam is presently like a stock magnum cam @ 220 deg @ .050 and you go to a bigger cam makes me wonder how low your cranking comp and lack of bottom end pop will be. I like the idea of pulling a head and measuring pist to deck, it would sure be nice before you buy a cam. PS: I do like the Lunati cams.

I will be pulling the heads. I got the the top end tore down enough to get the vally pan off and can tell it does have a purple cam in it. I am guessing its the smallest one (P4452783). I acquired a set of new edelbrock E street heads today from a guy local. They are the 75cc heads. I hope they arent way down there too but guess i will find out tomorrow.

 

[Don Frelier]

I will be pulling the heads. I got the the top end tore down enough to get the vally pan off and can tell it does have a purple cam in it. I am guessing its the smallest one (P4452783). I acquired a set of new edelbrock E street heads today from a guy local. They are the 75cc heads. I hope they arent way down there too but guess i will find out tomorrow.

That's a good cam in a 383

 

[rkohlman2013]

I have used a few Isky cams in engine builds over the last 4-5 yrs. All are performing well, no flat lobes, buuuuuuuuuuuuuuuuuut I used re-faced factory lifters to avoid lifter/lobe failure. Any lifter stock or aftermarket, that is 25+ yrs old will be a good lifter to have re-faced.
Isky cams are a bit more expensive & hopefully that s because they use as better quality cam core.
For your engine, I would use the 270 Mega.
It is veeeeeeeeeeeery easy to over-cam a short stroke engine that will be used on the street & convert it to dog status. I would also lose the TM6 intake & use a dual plane intake.

That's a good cam in a 383

Im going to pull the timing cover and see what number is on it tomorrow.

 

[rkohlman2013]

Im going to pull the timing cover and see what number is on it tomorrow.

Got the heads off, pistons are 366NP 0.060 over 05-202-C-10. Compression height is 1.848 in. Cam i pulled. It has 111819/270110 numbers than another number i am trying to make out.

Quick google search got nothing for cam numbers. It says made in usa, and the first 5 inches between the lobes is purple so??? Should have found sonething

 

[rkohlman2013]

Got the heads off, pistons are 366NP 0.060 over 05-202-C-10. Compression height is 1.848 in. Cam i pulled. It has 111819/270110 numbers than another number i am trying to make out.

Quick google search got nothing for cam numbers. It says made in usa, and the first 5 inches between the lobes is purple so??? Should have found sonething

 

[BSB67]

That's an unfortunate piston. Even with the 915 heads, it's probably about 8.5:1 CR.

 

[rkohlman2013]

That's an unfortunate piston. Even with the 915 heads, it's probably about 8.5:1 CR.

Yeah i measured them at 80 thou in the hole. Using summit compression calculator it comes out to 8.8:1 with the .027 head gasket thickness with 75cc heads with the 4.31 bore x 3.375 stroke….. still cant find any info on the cam numbers…..

 

[RemCharger]

Measure the lobe vs base circle. Times by 1.5

 

[Don Frelier]

Yeah i measured them at 80 thou in the hole. Using summit compression calculator it comes out to 8.8:1 with the .027 head gasket thickness with 75cc heads with the 4.31 bore x 3.375 stroke….. still cant find any info on the cam numbers…..

But the heads may be 78-80 so 8.8 would be maximum. Take a piece of lexan and a burrette and measure a couple chambers. You may want to consider cutting them down?

 

[rkohlman2013]

But the heads may be 78-80 so 8.8 would be maximum. Take a piece of lexan and a burrette and measure a couple chambers. You may want to consider cutting them down?

Im just going to run it. I will have some 906 heads and a TM6 intake for sale soon. Ordered a dual plane edelbrock and picked up a set of 5090 Edlebrock heads since it was tore down anyways. Cam that is in it seemed to pull hard. Cant really identify it but did find a Melling 111819 number which is basically the same with a little more duration than the P4452783 purple shaft. Have some adustable harland sharp rockers and 8.250 push rods in the mail coming soon. I apprecaite all the information and help with 383 cam info.