383 Questions

[73Runner4spd]

I was rummaging through craigslist the other day I found a 383 with a steel crank...not sure if its a factory steel crank or an aftermarket but it also has what he said were pop up pistons, I'm assuming they're just domed instead of flat tops. He didn't give me any info on the pistons them selves bore or deck height but he said he ran 906 heads without having any work done to them. I didn't think you could run unleaded gas on the 906 heads...correct me if I'm wrong. He claimed it had 11 to 1 compression with those heads. Sounds like it would be a screamer but I just don't know enough about it. I'm going to look at it tomorrow night. Now I know with my lt1 383 stroker motor I can get away with 12 to 1 compression on pump gas. 11 to 1 on a big block mopar seems a little steep to me. Are there any good afermarket aluminum open chambered heads available for these. I'm assuming the 88cc mmeans open and the 84ccs are closed. Yet again correct me if I'm wrong. Just don't want to buy a boat anchor but he's only asking 800 for it and it seems reasonable. If I buy this I will bag and tag my # matching 400 and the 383 will be mated with a 4 spd and 3.55 rear. Thanks in advance

 

[super-bee_ski]

383 questions...

73Runner4spd,
Well, you have a lot of questions here. Here is a little help...
1. Edelbrock sells a great aluminum head for the 383/440 (based on 906/442)
2. "Pop up pistons" could mean MOPAR style piston that sits above the deck.
3. 906 & 442 heads run on unleaded all day long. easy fix.
The big qusetion is: how much to buy this 383 and how much do you need to invest to make it run correctly.
Lots of smart guys on this Forum. One (might be Cranky?) always quotes:
"Fill your library before you fill your garage"
NOTE: apologies to anyone and everyone, I cant remember who's quote that is BUT it is so true.
Super-bee_ski
:iamwithstupid:

 

[trimmer]

I think all 383's have a steel crank. Most, but not all 400's have a cast crank. If you are using a automatic you will need a different converter. If you have a 4 speed you will need a different flywheel to compensate for the different balance. But I could be wrong, I was once but that was a very long time ago. lol

 

[Kernel Sanders]

1971 383's have a cast crank but I think that is the only year and I beleive the last year for the 383's

 

[73Runner4spd]

I think all 383's have a steel crank. Most, but not all 400's have a cast crank. If you are using a automatic you will need a different converter. If you have a 4 speed you will need a different flywheel to compensate for the different balance. But I could be wrong, I was once but that was a very long time ago. lol

I think all hp 400s infront of 4 speeds came with forged cranks

 

[73Runner4spd]

73Runner4spd,
Well, you have a lot of questions here. Here is a little help...
1. Edelbrock sells a great aluminum head for the 383/440 (based on 906/442)
2. "Pop up pistons" could mean MOPAR style piston that sits above the deck.
3. 906 & 442 heads run on unleaded all day long. easy fix.
The big qusetion is: how much to buy this 383 and how much do you need to invest to make it run correctly.
Lots of smart guys on this Forum. One (might be Cranky?) always quotes:
"Fill your library before you fill your garage"
NOTE: apologies to anyone and everyone, I cant remember who's quote that is BUT it is so true.
Super-bee_ski
:iamwithstupid:

Good information, thank you. It comes with a set of 906 heads I just thought you couldn't run them on unleaded gas. If I could get a way with running them this year I would put aluminum heads on it next year. The pistons are forged TRW. If they go passed the deck wouldn't it limit the heads that I can use? If so what in your opinion do you think would be my best bet for heads. I like the sound of 11 to 1 compression pony wise but I'd like to be able to put pump gas in it.

 

[trimmer]

Yes i think '72 & '73 400's with a 4 speed have a steel crank. Also I think cast cranks are not machined for a pilot bearing (bushing) although we have had a few machined to accept one. I was unaware that '71 383's had cast cranks. Hey I learn something new everyday. But I still reserve the right to be wrong on a regular basis. Just goes to prove when you get to be my age lots of cob webs form in your brain and I reckon a lot of information is deleted or just turns to dust. Good Luck with your project. I have a few spare 383's and 440's if y'all need one.

 

[73Runner4spd]

So I ended up picking up the motor for $700. The pistons had some carbon build up but they are dome pistons claimed to have 11 to 1 compression. It has a mopar purple came in it. I believe it to be the .484. The 906 heads it came with could def use a valve job But that is ok as I am probably going to end up putting Stealth aluminum heads on it. The cam appears to be brand new but I will still probably swap it out if other cams would respond better to the Stealth heads and the compression. With that being said, do you think those heads would mate well with the pistons I have? and which cam would mate best with those heads? I will also be putting a carb on it similar to the carb the guys from mopar magazine used to obtain 455 hp and 456 ftlbs on a relatively stock 383 with bolts ons and cam. I have a set of hooker comps going on it as well already. Thanks guys. I feel like such an idiot when it comes for big block mopars. To much research going into my sbc build -_____-

 

[scotts74birds]

Myself, I would get a stroker kit! 450 cu.in. Or a 496! http://www.musclemotorsracing.com/stroker-category/383-stroker-kit-article.html

 

[moparmarks]

71 383LP 2-bbl w/ auto had a cast crank. All 4-bbl and all w/ manual had a steel one.

 

[73Runner4spd]

Myself, I would get a stroker kit! 450 cu.in. Or a 496! http://www.musclemotorsracing.com/stroker-category/383-stroker-kit-article.html

Haha about that, I took the pan off this morning before I had to go out to class and noticed that the crank had been cut, I didn't have time to look for numbers but seeing how its cut I'm assuming that it is a 440 crank. Upon further investigation I will let you know what I find out. Not sure how I feel about this lol

 

[73Runner4spd]

Ok, so I pulled it all apart, its a factory 383 crank and rod balanced with forged Venolia domed pistons. Sending the block out to get magnufluxed and bored out as it is a standard bore, also having the crank polished while its at the shop. I noticed something got stuck in my #8 rod bearing but it only affected #8, Also the piston skirts look a little scuffed so I will be replacing them. Not sure if the 383 would run properly on 93 octane with 11 to 1 anyways so maybe I'll aim for something in the 10.5 to 1 range. I was looking at this for a kit
http://www.summitracing.com/parts/FEM-CSMHP738-311/
But it advertises 8.94 to 1 compression with 88 cc heads and that seems a little low. I currently have 915 heads with valve job on my 400 which is in the car currently. My question is how do you think the 915s would perform on that rotating assembly until I can afford some 75cc indy ez heads later on? Also what do you guys feel would be the best cam for the 915 heads. Or do you guys recommend not using that rebuilt kit and going with a higher compression piston. I dont mind doing a cam swap in a year or two when the indy's go on. The car as is has a 400 with mopar .484 purple cam, 915 heads, Edelbrock torquer 383 intake, Edelbrock 1407. It is a 4 speed with 3.55 suregrip. The 383 I bought came with a brand new purple cam but I figured it is a little out dated for what is out now. For the 383 I was thinking. The 915 heads, Using the same intake but replacing the carb with a Holley 4150 mechanical secondaries, Hooker Comp longtubes. Thanks for the input again. Sorry to be a pita about this.