383 build (help need advise)
Hey guys i'm going to be doing a 383, I have a 1950 chevy bel air with 1967 camaro sub frame with a 327,th250 trans 8.8 rear end with 2.73 gears, long story short its a small journal so I went and bought a 350. Here's the plans get the machine work done on the block bore/oil pan rail cleanced/rods cleanced and balanced. And install the following parts scat 9000 series crank 3.75 stroke and 5.7 rods, clevite bearings, .110 dished speed pro hypereutetic pistons, rpm performer cam 234/244 @ .050 -.488/.510 lift its says power from 1500-6500 rpms. Dart iron eagle 200cc runners 64cc chambers 2.02/1.60 valves 1.437 springs striaght plugs. Crane energized roller rockers 1.5 ratio. Comp cams guide plates,and hi tech push rods. cloyes roller timing set. Professional products powerforce damper. Rpm air gap intake, 600 cfm edelbrock carb off the 327. I planning on a 700r4 and 4.11s. So what do the pros think will this be a good combo, if you see anything wrong PLEASE just say so your opinions count!! Also what do you think the compression ratio would be and about what kind of hp. and torque numbers thanks guys i read on here all the time but this will be my first post. :welcome: kyler
Welcome to the board. With a 4.030 bore, pistons .025 in the hole, flat tops with valve reliefs, .041 gasket and 64 cc I come up with 10.21, pushing it just a bit for pump gas depending on your tune.
So with the dished pistons I should be a little lower right, how much do dished pistons usally lower the CR?
SB-CHEVY: 383 w/5.700 Rod 0.110 dish top piston with 4-valve reliefs. 9.63 Comp. Ratio with 64cc Head 8.62 Comp. Ratio with 76cc Head
You will need a high stall converter for that cam.
3000 minimum 3500+ for max performance.
It does not work well with a stock torque converter.
If you want to see the actual benefit from OD.
( engine rpms slower at hiway speeds to save gas)
You would want a different cam.
That cam likes rpm. It is inefficient at a slow engine rpm. Like when cruising in OD
too much duration for that.
A cam choice is a series of compromises.
It cannot be a big cam and a small cam at the same time.
Thanks guys, so f-bird 88 should I just go with a 350 trans and forget the 700r4 overdrive trans I was just thinking the od would be nice for 4.11 gears at highway speeds I also liked the low 1st gear im not to awfully concerned about good mpg , I was thinking a 2800 stall just cuz i'll be driving around town on weekends and I didn't want to create to much heat from the converter. The only bad thing is 98 percent of these parts are already in the engine the cam is one of them. Where do u think that cam produces its most power? 3200 3300 rpm?
Ya I would not bother with the OD trans for a ton of reasons.
A th350 w a shift kit and some quality clutches gets it done.
The motor wants to rev with that cam.
The amount of heat a converter makes is totally dependant on how
much you drive around rugging the throttle. If you are constantly rugging it from a stop light ya the trans is going to heat up.
The stall speed of the converter does not have that much to do with it.
A 10" 3000 stall and a 10" 3500 stall will make the same heat.
The 3500 stall is the one to get if you want max performance with that cam.
Excessive heat is caused by poor converter design and mismatching a high stall with a low gear like 2.73 but 4.11's will be just right.
The 4.11's allow the converter to function correctly on the street and not
heat up or slip excessively under normal driving.
I;d get a th350 and the 10" 3500 stall.
The engine is quite happy cruising at 3000+ rpm on the hiway.
And the converter will not run hot.
Get a trans cooler too.
If I was stuck on wanting to use a OD trans with a stock or mild converter
I would rethink the cam choice even if its already in the motor.
That cam doesn;t get real busy until 3000+ rpm.
It works very well with a generous converter and gears.
The th700r4 trans is a dog.
My two cents FWIW,
If I were you I'd buy the Scat crank for six inch rods so that you can get the rotating assy. internally balanced, as it sounds in your post(big cam, 200cc heads) you'll be turning allot of rpm. You didn't say if it was a one or two piece real seal block, so I can't list a PN.
I'd also buy the Scat 2-ICR6000-7/16, 6" I-beam rods with the ARP cap screws and bushings for floating piston pins/ 6" rods.
For a little more detonation tolerance I'd buy Forged pistons for floating pins.
I'd also buy a Powerbond balancer PN PB1046ST. Has engraved markings and a better reputation than the Powerforce dampner.
PS I'm no pro!
Ssmonty sorry its a 2 piece rear main high nickel nodular capped block. i'll look into going with the forged crank 6.0 rods and forged pistons and see if I can afford it. Thanks for your suggestions! :D
F bird 88
well you've talked me into a th350 trans! Haha! Which brand do u prefer for transmission overhaul kits and converters B&M, TCI or Hughes, I was looking at a TCI streetfighter converter part# tci 241000 in the summit catalog and the TCI 328800 overhaul kit. Also for gears is Richmond gears a good brand and whats the best way to make it posi a Detroit locker truetrac differential?
Thanks for all of your help so far guys im 25 yrs old and trying to learn from you gearheads that had the privilege to experience the days of the muscle car! Haha
I would stick with the 700r4.
You can use it in 3rd gear and you're driving around 1:1 same as the th350.
Then when you get on the highway and get up to 70-75 and all the rpm's and exhaust noise start to grind away at you, throw it into overdrive.
At 75MPH, with a 26" tire, rpm's will be 4090.
Throw it into OD and and it drops to 2788.
I'm not sure how it would run at those rpm's with that cam, just showing how a 700r4 could be useful especially with 4:11's.
Go with the 700r4 and get a different cam. More lift, less duration, preferably roller.
Sorry if I was miss-leading, but you can get the Scat 9000 series cast crank which is much less expensive than a forged one,($242 vrs. $630) and get the job done. Summit PN SCA-935056(Scat's long PN 9-350-3750-6000) is what I'm referring to although they have an incorrect description by calling it a 400 instead of 350 crank. Look at the specs and you can see that the main journals are 350 size. Better yet, check out Scat's site for part numbers, and specs.
The rods I mentioned are a work of art for the money($330) in my opinion, and a good buy even if you don't get the forged pistons. Summit pn SCA-26000716(Scat's pn 2-ICR6000-7/16). They have ARP cap screws instead of thru bolts, and the big end has construction qualities more like an H-beam rod. Mine measured less than .001" in length variance between all using a set of Mitutoyo calipers. I admit calipers aren't the best method for measuring rods, but they are pretty consistent, and I've heard about other rods being checked the same way and finding much more variance in rod length.
The only drawbacks to using the 6" rod (IMO) is that allot of pistons designed for them have to use rail supports for the oil rings(not all), and the pistons price may be a little higher.
PS If this is for the street I'd agree with AP72 and go with a smaller cam or its gonna be a dog where it will spend most of its time. That is if its a hydraulic lifter. And there rpm band is a little on the wide side.
Ssmonty thank you i'll rethink my setup, i'm going to stick with the cam though just becuase I already have it if im not happy I can always recam it later down the road.
What size cfm carb would work best for my setup I found a cheap king demon with removable sleeves if I were to get green sleeves for it, it would be 795cfm would that be pushing it for size i've been told buy local guys 750cfm would be a good choice and that the 600cfm that I have now is pretty small.
for me if i were to drive it on the street more than on the track id stick with the 5.7 rods that you have listed but it will perform great at the track aswell just with the 6" rod puts the pin up in the rings, it is very easy to make power and tq with a 383 and id deff use a better carb to feed the need, pn#4779 750cfm holley will put it out, but it you can aford a few extra bucks the holley street hp 750 is a nice peace, with the cr being around 9.7 will make it good on 93 octane, you can get easy 600hp out of a 383 on pump gas with the right goods with your combo with a holley prb around 420-450hp my guess, my wife's cuzin has a 98' s10 with a 383 in it 4:10 gears and a tci th350 just let me tell ya the 29/12.5/15 mickey sportsmans dont stand a chance, he drives it around town all the time, even when it uses 114 race fuel!
you could make that king demon work, iv seen plp put 850's on 355s lol, but you could jet it the way you want it put the right power valve in it too... but heres some food for thought this combo puts out around 480hp, tfs 215 heads, comp xr282hr cam, on pump gas! and scat 9000 series rotators are a good choice...
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