Sorry, I thought the title was catchy. Anyway, has any tried the rotating assembly found at http://www.ptperformance.net/chevrotassem.html ? I'm looking for a budget 383 rotating assembly, and this looks pretty good. The last price sheet I have from powerhouse lists it at the same price ($899), but has less compression. The 10:9 compression of the above listed assembly seems ideal. What are your thoughts? Any good places I might look, and does anyone have any dyno graphs or figures on their 383 powerplants? (BTW, this would be either a MiniRam, RamJet, or Edelbrock Performer RPM motor, with a power band from 3k to 6k). Also, I'm only interested in 2pc. rear applications.

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86 IROC-Z, Retired for winter, weird oil leak (drains out in about 3 minutes), new 355 other than that, TPI, 700R4, edelbrock headers, removed AC/Air pump, heater plate conversion - no heater (loL). 14.8@90MPH

[This message has been edited by Slow Iroc (edited January 01, 2001).]

 

you sound exactly like me when I first started on my 383 but let me save you some time and mistakes. I talked to many people for several years about 383's. the 2 points everyone agreed on was you have to run 6" rods and have it internally balanced. a 6" rod gives you a better rod-stroke ratio, has better cylinder fill and combustion due to the time the piston stays at TDC and BDC which allows you to get away with more compression without fear of detonation and it also gives you a better rod-piston angle which lessens the side load and friction on the piston skirt to sidewalls which greatly increases engine life. The reasons for the internally balancing is that it tremendously decreases the stresses on the crank and block and all but eliminates the wear on the front and rear main bearings. Externally balanced engines use a weight on the flywheel and the balancer to counterbalance any imbalancing to the internals of the engine. This allows the crank to "flop" around more which creates stress. It also creates a lot of friction and load on the front and rear main bearings which shortens their life. By internally balancing you make the whole rotating assembly balanced throughout the engine. Think of it as balancing a tire with weights only on the inside edge versus balancing with stick-on's throughout the width of the rim. You can't properly balance a tire by putting the weight on the inside edge and the same is true with an engine. So I started my hunt for parts from there. My first choice was to use a cast steel crank I found for 350 bucks but I started checking around and found cast steel to only be moderately stronger than cast iron and that you cannot internally balance one. The problem with internally balancing a 383 is that it does not balance like a 350 where you just remove material from the rod caps. There is no weight on the caps to remove so you have to add weight to the crank filets. To do this they drill a hole in the side of the crank filet and add Mallory metal which is an extremely heavy and expensive material. It costs around $100 per ounce and I got estimates of between $300 and $800 to do so which scared the hell out of me. So I started looking and found a generic 5140 forged crank for 550 and started looking at rods and pistons. I quickly found out that cheap pistons for a 6" rod 383 are non-existant and I knew I wanted to run nitrous down the road so I ended up choosing to run SRP pistons at $475 a set. I also needed to end up with around 10:1 with my 64cc chambers and SRP has a set that were perfect. I could have got a cheap set of forged rods for around 200-300 but I decided to get the Eagle h-beam lightweight rods for 419 so I wouldn't have to worry about breaking them. before I got my stuff I found I could upgrade to a 4130 crank for only about 300 more so I called to order my stuff. I found that crank on backorder so I got the next step up for about 100 more which was a lightweight Cola 4130. When I had the engine assembled I had a very pleasant suprise come about when they balanced it. By choosing all the lightweight parts, I didn't have to use any Mallory metal so they were able to balance it by just removing some material from the crank filets and I only had to pay the normal 110 balancing fee! So all in all, I got a much stronger bottom end for the same price just by buying the lighter stuff. I only made one mistake with my 383, 2-piece rear main. I started with the 2-piece because there were no cheap 1-piece cranks available which is probably the same reason you want 2-piece. I have installed 3 rear mainseals now and still have an oil leak. so let me help you out. Go find a 1-piece block, get a good lightened 4130 forged crank, lightweight 6" rods, lightweight forged pistons and have it internally balanced (350 balancer and flexplate). You will not regret it. I talked to one guy to took the cheap route and used one of the "affordable kits". He was in the process of removing the engine to scrap the parts and put good stuff in. After hearing that I made my decision and took the plunge into the forest of Forged steel and I've never taken a look back.

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Kyle Osterholt
Okarche, Oklahoma
ASE Master Certified
86 T/A 383 TPI
89 TTA #1002 T-top/Leather
89 TTA #1358 Hardtop/Leather
80 T/A Pace Car
73 Opel GT

 

Wow, thanks for the great reply! I'm building this on a college budget, so thats why I was looking for the best prices. After hearing what you said, a long rod 350 might be my better choice I suppose. I was attracted to the free balancing, the 5.7in rods (which from what you say, might be better used as paper weights), and the new crank. While I have your attention, will a 6in rod'ed 350 help smooth out the idle, and improve the rather poor streetability that the Edelbrock Performer RPM cam dictates (my main reason for going 383)? Thanks so much for sharing your knowledge.

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86 IROC-Z, Retired for winter, weird oil leak (drains out in about 3 minutes), new 355 other than that, TPI, 700R4, edelbrock headers, removed AC/Air pump, heater plate conversion - no heater (loL). 14.8@90MPH

Next project (think I'm going to scrap the IROC)- mid 80's monte carlo, 383, edelbrock performer RPM intake, cam, holley double pumper carb, sportsman 2 heads, NOS. Hoping mid/high 12's on motor, mid 11's on spray.

 

a long rod 350 runs great. My buddy built one out of his 93 t/a and gained about half a second just from the switch to the long rod engine. He installed Eagle I-beam rods with SRP flat top pistons. I wouldn't expect any change in idle characteristics though. I'm not firmiliar with that cam. make sure that cam is designed for a TPI otherwise you waste your money. these engines take a totally different grind than a regular sbc because of the long intake runners which changed their rpm range. I would suggest getting one from Linginfelter myself. your 86 should have regular hydraulic lifters which is what I have and my cam only cost 185 from LPE and it is a much better cam than my TPIS cam ever thought about being.

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Kyle Osterholt
Okarche, Oklahoma
ASE Master Certified
86 T/A 383 TPI
89 TTA #1002 T-top/Leather
89 TTA #1358 Hardtop/Leather
80 T/A Pace Car
73 Opel GT

 

Oh, sorry, prehaps I should clarify. It's going into a mid 80's monte carlo, RPM/MiniRam/RamJet style intake, big cam, big gears, high stall convertor. Thanks for the input though