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    Results 1 to 16 of 16
    1. #1
      Join Date
      Feb 2008
      Location
      Sesser, Il
      Posts
      490

      383 SBC rebuild questions

      I'm in the planning stages to rebuild my 383 street engine. My mains questions concern pistons, compression ratios (static and dynamic), and cams.

      First off, here's what I have to work with:

      350 block with cylinders that mic out ot about 4.034". I'm going to have it bored and honed to 4.040". I'm looking to have it decked to .000 after engine mock-up. I'd like to see .039" - .042" quench with the Fel-Pro 1010/1003 gasket. AFR recommends the 1003.

      AFR 190 CNC heads...started out as 76 and milled by AFR to 68cc. They were then milled .008" to clean up slight engine damage (busted piston). Was told the final cc was about 66cc but I will measure the cc to be sure.

      Cast steel (brand unknown...has "3004" printed on front counterweight) crank that needs the rod journals polished or turned .010". Mains will only need polishing and remain std size.

      Accel SuperRam intake, runners, and plenum. Using the 89 Camaro ECM and will be tuned by PCMforless for a base chip.

      1 5/8 Hedman shorties or 1 3/4 Headman longtubes.

      Aftermarket T56 with 3.42 gears in an 86 Cutlass.

      Since this is a street engine I'd like to keep compression at about 9.5-1 with 18cc dished piston or 10-1 with 12cc dish. I'd like to see this engine get at least 100,000 miles. Can a forged piston have this lifespan or should I stay with a hypereutectic? Enginge will not know nitrous or rpm beyond 6000. Pressed pin or floating pins? I'd also like to stay with 5/64 rings. I've been looking at KB hyper and forged pistons along with Probe FPS forged. Must keep pistons under $400 set due to budget. Ideas?

      Hydraulic roller cam. I'm looking at 3 differant cams, all by Comp Cams. I will have them all ground on a 112 - 114 LSA.
      XR270HR 218/224 .495/.502
      XR276HR 224/230 .502/.510
      XR282HR 230/236 .510/.520
      All the XFI cams listed with the 113 LSA has lifts of .570 plus, more than I care to run. Cam ideas?

      I'd like to see this setup run to at least 100k miles and get reasonable (20-25 mpg hopefully) mpg. It will be a mild to hot street cruiser, not a track car. I'd also like for it to sound as good as possible.

      I know I ask alot of questions and I "may" be expecting alot of this engine. I'm open to all ideas and vendors are welcome. I will be building this engine myself.

      Doug

      Doug Gulley

      66 C10 383, AFR 190, Accel SuperRam, Hyd Roller 230*/236* 280XFI, aftermarket T56, *under construction*


    2. #2
      Join Date
      Oct 2007
      Location
      ridgefield ct
      Posts
      876
      well i have a xe274 in my 9.7:1 CR 383 and i wish i'd gone larger. there's no noticeable cam lope. and although it's fun there's some major torque on the botton end. enough that i'd like to change the cam timing to move the power band up some.
      any special reason you're keeping the ECM? i have mine for the knock retard (and i had the parts) but i don't know if it's worth it or not.
      work in progress--for the next 10 years.
      1987 monte carlo ss 383ci, 9.7:1, xe274 cam, vortec heads, 200r4, 3.73 posi.

    3. #3
      Join Date
      Feb 2008
      Location
      Sesser, Il
      Posts
      490
      Quote Originally Posted by megaladon6
      any special reason you're keeping the ECM? i have mine for the knock retard (and i had the parts) but i don't know if it's worth it or not.
      I'm mainly using it cause it's all I have. I'm on a budget and the aftermarket ssystems are beyond my finances. I may update to the 90-92 SD in the future but after I get things running again. Any suggestions?

      I noticed you are running a flat tappet cam. I previously ran a 218/224 110 flat tappet in a 350 and then went to a 218/224 112 hyd roller when I switched to the 383. Even though the durations are the same (at the measured .050" lift) the roller is really a bigger cam. More duration due to quicker opening.

      Doug
      Doug Gulley

      66 C10 383, AFR 190, Accel SuperRam, Hyd Roller 230*/236* 280XFI, aftermarket T56, *under construction*

    4. #4
      Join Date
      Oct 2007
      Location
      ridgefield ct
      Posts
      876
      i would have run a roller if i'd had the money or some more info on ZDDP/oilat the time. although the XE series of cams supposedly opens just as quickly as a roller. one of the car mags tested it and they did come out pretty even.
      work in progress--for the next 10 years.
      1987 monte carlo ss 383ci, 9.7:1, xe274 cam, vortec heads, 200r4, 3.73 posi.

    5. #5
      Join Date
      Dec 2006
      Location
      Petersham ,ma
      Posts
      522
      1st id say lose the 342 gears with the t56, my afr headed 355 in my nova nailed down 19 mpg with 410's and a gas eating holley 750 hp/dp on it, with 342's 6th gear will be unuseable. move up to some 373's atleast. as far as forded vs hyp pistons i have know idea? for free power and fuel mileage go with the lightest piston you can afford.

    6. #6
      Join Date
      Feb 2008
      Location
      Sesser, Il
      Posts
      490
      I have been considering moving up to the 3.73 gears. My aftermarket T56 has the .63 6th gear so I think that would be about right. If I had the OEM T56 I'd run the 4.10's myself.

      I'm leaning toward running the hypereutetic for the tighter cyl wall clearance. I'm still not sure about whether to run 9.5 or 10-1 compression and which cam to run. Decisions............

      Doug
      Doug Gulley

      66 C10 383, AFR 190, Accel SuperRam, Hyd Roller 230*/236* 280XFI, aftermarket T56, *under construction*

    7. #7
      Join Date
      Aug 2008
      Posts
      67
      I run a xr282hr in my 383-perfect match for 10-1 with afr195's
      I also run KB hyper's with no problems

    8. #8
      Join Date
      May 2005
      Location
      Fontana, CA
      Posts
      4,959
      Country Flag: United States
      With those heads too little a cam is a waste, and not just from a lost power perspective. THe 276 at least if not the 282. For what you want the hyperutectics will work fine. Pressed will last as will floaters, either way you'll be fine. The big thing is that RPM and load are bigger engine killers than HP. 9.5:1 v 10:1 means premium gas either way. The higher comp will yield more power without sacrificing fuel efficiency and may increase hwy MPG since there will be less demand to keep the revs up since the engine will have sufficient low end power (depending on powerband and whether you change those rear gears). For a treet car, go shorties or Tri ys as anything 1 3/4 + long tube is a drag (litereally). Also, wide LSA roller cams sound nowhere near as lopey as their narrower counterparts. Compare a magnum 280 cam in a 383 to that 282 and it is night and day. But for good reliable power and street manners, I'l take a wide LSA roller any day of the week.

      Hope that answers most of the questions.
      Nick R.
      69 Camaro - 383, 700R4, 12 bolt 3.55, Hotchkis, Bilstein, Global West, Morris Classic
      08 HHR SS - Still Stock for now
      Do you still believe in all the things that you stood by before? Are you out there on the front lines, or at home keeping score?
      Do you care to be the layer of the bricks that seal your fate? Would you rather be the architect of what we might create?

    9. #9
      Join Date
      Feb 2008
      Location
      Sesser, Il
      Posts
      490
      I appreciate everyone's comments and will take the given advice

      Nick
      I think I will go with the 10-1 and the XR282HR on either a 112 or 113 LSA. I also have a set of Hedman 1 5/8" shorties already and may just stick with them since I have them. Being a street car and most of the time will see idle - 3500 more than 3500 - 6000 the extra gain in top end won't be worth the extra cost and slight torque loss.

      Yellow Heap
      I'm guessing your cam is a 110 LSA? Got any idle vacuum readings just for curiousity sake? I am running EFI and need to keep the vacuum up somewhat.

      Jasonsnova
      I have decided to go up to the 3.73 as the 3.42's would lug the engine down with my other setup and since my bigger cam will have a higher powerband the move up will be a good one.

      For a good mix of street driver and pro-touring I believe I've come up with a good compromise. Thanks all and happy motoring!

      Doug
      Doug Gulley

      66 C10 383, AFR 190, Accel SuperRam, Hyd Roller 230*/236* 280XFI, aftermarket T56, *under construction*

    10. #10
      Join Date
      Aug 2008
      Posts
      67
      Yes 110 is correct,at 750 rpm- 14 inches of vacuum when warm and a decent idle.
      This cam rocks.
      I can load the car down to 600 rpm up my 12% + grade drive way in second gear,no buckin or snortin.
      With a wider lsa and fuel inj I can only imagine!
      My first gear overall is 10.82,I would shoot for something similar with your t-56 and enjoy the over drive as my motor easily pulls strong from 2000 rpm

    11. #11
      Join Date
      Feb 2008
      Location
      Sesser, Il
      Posts
      490
      My Aftermarket T56 has a 2.97 1st and .62 6th gear. I'm thinking about going to a 3.73 instead of my 3.42 gears. The 3.73 will give me an 11.07 1st gear ratio overall. I'm looking forward to getting this thing going!

      Thanks

      Doug
      Doug Gulley

      66 C10 383, AFR 190, Accel SuperRam, Hyd Roller 230*/236* 280XFI, aftermarket T56, *under construction*

    12. #12
      Join Date
      Dec 2006
      Location
      Petersham ,ma
      Posts
      522
      86 cutless, go to afr's web site they have a combo on there with a comp roller that made 500+hp at only 5800 rpms ...awesome street engine.....it is probally gonna be my next engine,
      as far as cams im running kind of on the small side as far as duration its a lunati voodo, #60103, but i also run 1.6 roller rocks which up's it a little bit, it has awesome charactoristics, i can lug it way down to 1800on the hwy and it has good top end power too

    13. #13
      Join Date
      Feb 2008
      Location
      Sesser, Il
      Posts
      490
      I did go to the AFR site and my engine is very simular to the 480hp version. They used 9.5 compression and the 180cc heads where I'm planning on upping the compression to 10-1 and using my 190cc heads. Same cam with the exception that they used the 110LSA and I'm thinking on widening that to a 112LSA to better work with my SuperRam EFI.

      Sound okay?

      Doug
      Doug Gulley

      66 C10 383, AFR 190, Accel SuperRam, Hyd Roller 230*/236* 280XFI, aftermarket T56, *under construction*

    14. #14
      Join Date
      Feb 2008
      Location
      Sesser, Il
      Posts
      490
      I tnink I may have my engine combo sorted out unless someone has any other ideas. Here goes.

      What I already have:
      AFR 190 untouched heads with 66cc
      4.04 block
      3.75 cast steel crank


      My assembly parts to be bought:
      12cc dished pistons (hyper or forged?) (pressed or floating?)
      5.7 stroker rods (depends on press or floating pistons)
      230-236 hyd roller on 112 LSA

      Not knowing the exact timing on the cam (I used the 230-236 with 110LSA for my computing...the 112 will be slightly less I know) and .038 - .041 quench with I "should" be at about 10.04 cr with 8.05 dynamic compression. I would rather err on the safer side. With an 18cc dished piston it should put me at 9.45 - 1 cr and 7.60 dynamic. I think I'll go with the 12cc combo.

      Doug
      Doug Gulley

      66 C10 383, AFR 190, Accel SuperRam, Hyd Roller 230*/236* 280XFI, aftermarket T56, *under construction*

    15. #15
      Join Date
      Aug 2008
      Posts
      67
      I would run the 12 cc combo,better match for the cam.
      I run 10.38 comp,.038 quench with a carb,no probs even in hot(100+) weather.
      I think you could get away with 7cc flattops if your heads are really 66cc's with a tight quench, open lsa and a good tune on your fuel injection but it would be real close
      At 10-1 you might even be able to burn the cheap stuff with your setup,a smart ,safe choice.
      I think your gonna give those 30 pound injectors a REAL workout!

    16. #16
      Join Date
      Feb 2008
      Location
      Sesser, Il
      Posts
      490
      Thanks! I think I will do the 12cc combo. I'd rather be safe than sorry... detonation is the reason for my rebuild in the first place and thus, all the research (and questions!!!). Thanks again!

      Doug
      Doug Gulley

      66 C10 383, AFR 190, Accel SuperRam, Hyd Roller 230*/236* 280XFI, aftermarket T56, *under construction*





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