[70 340]

When useing stock rods & pistons in a 383ci with a steel crank what sort of RPM can you rev them to also how much HP would it hold? I'm thinking of rebuilding the bottom end with a big cam and a set of mopar performance heads and a few other good parts but would like to know if anyone els has done something like this and what did it go like? Any info would be great.
Darryl.

[dave-r]

Power is not a case of just bolting on random performance parts.

Everything has to match the cam. The heads, the rockers/valve gear, lifters, intake, rear gears, ignition etc etc. Everything.

If it was that easy everyone would be doing it and making 500-600hp.

But to answer your question. It is not the pistons and rods that limit engine rpm. It is the rod and crank bolts.

But the lighter you make the rods and pistons the less stress you put on the bolts.

What compression is your engine anyway? You will need good compression for bigger camshafts.

[Eddie]

70 340, that 383 has ALL my respect. As Dave stated, get some ARP's on those rods or use lighter, stronger 4340 Eagle, Cat, Pep ect rods and replace the fasteners in the main caps with studs. Then get some decent heads and matching cam for the volume of the intake ports and let er rip!!!Those 383 are very tough, Big bore,(4.310) short stroke, lots of reliable high RPM power!I would also use solid lifters and matching cam with springs,(very important). www.440source.com has a lot of 383 parts at very reasonable prices. Yes, they are mostly outsourced but if you like me are on a budget then..... BTW, for you and everyone else. They are currently developing a set of aluminum heads for B/RB apps. and priced around 699.00 complete! cheap for a big increase in power!Available by spring of next year I think. These will be Eddies copies, but at a significant decrease in cost. 200cc intakes 2.14 1.81 stainless valves bronze guides, .535 lift springs.

[70 340]

Dave, I understand that you must make sure that all the parts match or it will work against each other. I think the compression is about 9.5:1 or 10:1 stock. I was going to use a set of ARP studs for the heads, crank and rods to hold it together. With the cam a MP 0.484 lift 284/284 duration part#P4120235. Match the heads to the cam and a single plane intake 4bbl 750cfm carb. The rear end is a 8 3/4 with 3.23 gear sure grip, thinking of going to a 3.90 or maybe a 4.10.

Airfueleddie, I will have a look at 440source and go from there. My 70 challenger is the main car for me the best of everything but I will not be driving that alot so for something that I can have a lot of fun in and not worrie about stone chips and other thing i'm building a A body with the 383ci for 90% street & 10% strip and just smoking the tryes of it but make it reliable. . Darryl.

[Eddie]

Sounds like you have a good plan. Planning is very important! BTW, I dont know your budget, but when you peruse through the 440source online catalog you will see stroker kits for 1199.00 unbalanced, 200.00-300 for balancing, that can boost your cubes to 500 from 383 CID,(without piston buttons). I am going with the 474 CID kit from them for my 400/474 project thats slowly coming together.

[dave-r]

I think the compression is about 9.5:1 or 10:1 stock. I was going to use a set of ARP studs for the heads, crank and rods to hold it together. With the cam a MP 0.484 lift 284/284 duration part#P4120235. Match the heads to the cam and a single plane intake 4bbl 750cfm carb. The rear end is a 8 3/4 with 3.23 gear sure grip, thinking of going to a 3.90 or maybe a 4.10.

Well you didn't mention any of that now did you?

The answer to your question then is no more than 7000rpm.

I really really wouldn't bother with that 40 year old design MP cam. Even the stock heads would handle that easily.
Get yourself a cam with the same sort of duration but a bit more lift.

[70 340]

I had a look at 440source today and seen the stroker kits for the 383ci very tempting but i don't think i could aford it. They have some very good quality parts at a very good price thanks for the link Edd

[Eddie]

No problem. Have you seen any of Dave Hughes Cams? He has as Dave suggested, a high lift cam without too much duration. www.Hughesengines.com also Comp Cams makes a fast rate of lift cam. An easy way to tell if your cam is fast rate of lift. Divide the adv. duratoin by the .050 duration. If you get 85% or better it's fast rate of lift. All the MoPar performance,(purple shaft), cams are actually 25+yrs. old and are desigend on GM cam blanks. The cam manufacturers design the cam to work with the minimum allowable lifter diameter, which is GM and Ford they only have .875 and .825 to work with,(MoPars are .904), as long as they "work" for the smallest lifter diameter, they will work for all engines and saves the company money,(cost accounting at it's finest), Dave Hughes takes a different approach and utilizes the .904 advantage thus increases the "performance" of the cam without any design compromises.

[70 340]

Thanks for your help. Dave r I hope I did not upset you in any way. 7000rpm is more then I hoped for that is great and thanks again

[dave-r]

Not at all.

Listen. Keep the bearing clearences on the loose side and use a heavy oil.

[Eddie]

Not at all.

Listen. Keep the bearing clearences on the loose side and use a heavy oil.

Very good advice Dave!!

[70 340]

I'll keep that in mind.