slowride

iTrader: (3)

Well I'm planning on fixing my new to me h/c ZO6 that lost #7 in the stock shortblock a few months ago. I've only owned the car for 4 months and 2 of them have been on jack stands I didn't do the work to it I bought it this way and drove it home from Texas. Car put down 445whp through the cats is what I'm told. It has 3.90's out back and the stock M12 "tighter" gearbox. I think the cracked ring land was do to lesser fuel quality/octane (I can get 92 or 93 with up to 10% ethanol where I live) and running stock injectors at this power level. I noticed some pinging, but only when it was cold out for the most part and I even started using Torco later on. I've got some SVO 30's now and plan on re-tuning it and probably getting HP tuners and a wideband.

The car had a set of CNC Cylinder Heads (Florida shop) 243 heads (~300 cfm at .600") with a 232 236 .575" 114+4 cam (XE lobe). The heads are around 58cc and it was running stock MLS head gaskets. It also has a ported tb, Haltek cold air intake, LG pros, stingers, tr6's etc. After tearing down the engine I noticed some odd cam and roller wear. The cam will either need to be fixed (if comp can) or junked. I purched some new Comp hyd replacement lifters already. I like to drive the car on the street a lot and taking it to the autox, road course and drag strip are all things I enjoy.

Well I talked myself into building a 383, but I'm having second thoughts now after purchasing most of the stuff (Eagle crank, Mahle 3.903 pistons and Compstar 6.125 rods) . After playing with some SCR programs it seems like I will end up with ~ 11.83:1 compression due to my heads being milled a lot and decking the block to bring the Mahle piston +.010 out of the hole (as others have said they are a tad short) to give me decent squish (.043"-.044") with the MLS GM gaskets I have. If I don't bring the piston out of the hole I'll end up with a large squish area unless I go with some Cometic gaskets or something. I know cam choice will allow a safe DCR, but I don't want any problems running the two fuels I mentioned above and don't know if it's advisable to run that high of a SCR on a car that sees a decent amount of use.

Can I run this setup safely or should I stick with a 347 which will drop the SCR town to the lower 11's (~11.1-11.2ish) and re-use the old cam or get a new cam if needed If I did the 347 I'd probably switch the pistons to the the correct Mahle 347 piston that already sits +.010 at stock deck height, use the Compstar rods and stock crank. The 347 costs less in parts, machine work and might be more managable for the driving I do. I kind of figured my gearing would be overkill for the 383 anyway. Whatever I do I want it to last for quite a while with good drivability, no stalling, etc. It seems like the 347 would be more reliable due to the whole piston speed thing, etc.

The old 232 236 cam was nice and lopey, but didn't surge or anything with the LG drivability tune it had. I am looking for similar results with this build. Any of you DCR/SCR cam experts care to help a brother out If you think the 383 sounds like it WILL work with my heads then any cam suggestions would be appreciated I was thinking something in the 235 240 600" area with a xer lobe, but it's just a starting point. I don't want a monster cam though. I plan on keeping my LS6 intake for now (90/90 in the future) and making ~460whp and 440wtq if using the 383 with the ls6 intake.

slowride

iTrader: (3)

Anyone have any ideas on the 383 working ok with my fuel octane and the high SCR? Maybe I should have put this in advanced tech?

383ss

iTrader: (14)

just get a cam to get your DCR down so that you can run 91 octane gas with no problem. you should be fine with 11.83 compression. the 383 will have a ton more power down low and be a lot more fun to drive

I would call a sponsor to get it spec'd

slowride

iTrader: (3)

You don't think my gearing would be excessive (seems like I only have 5 gears anyway as 1st is short)? After searching 383 stuff for a few weeks I see you use to have one, but have switched to a 408. Any reason for this aside from more power and iron block foundation?

I know the above post is really long, but I wanted everyone to see what I was working with. After paying $30k+ for the car I'm not really in the mood to break the bank. I've been working with Trevor at Texas Speed for most of the parts and cam choices, but he has been hard to get in touch with lately.

David Gordon

iTrader: (1)

I have a Vette w/ 3.90s and I have a small (by today standards) stroker motor and I love it. I dont have your shorter tranny gear though. I had a heads and cam motor before this that made like 445 rwhp and now I have the stroker that has made 489 rwhp and the difference is night and day. The smaller motor was harder to drive due to being more radical abd the bigger motor is much more fun. Instead of the 383 Texas Speed can build you a 395 cu." for the same price or close to it. The 395 makes more torque and hp as well.

slowride

iTrader: (3)

I figured with the extra gear I could rev the 383 with a little less piston speed and I can use off the shelf Mahle pistons. I'm into the un-balanced rotating *** less than $1900. What do you guys get for milage out of the 383+ all stroke setups? I don't want to replace it 2 years from now. I say that now, but ask me in 2 years when I have something 400+ci

I just want it to run well without any detonation problems with the pump fuel around here. If I get to a road course I'll splash some 100+ unleaded or Torco at it. I think the ls6 intake will be the bottle neck, but I still should be able to hit 460whp 440wtq with the right cam and 92 octane don't you think? With all the talk of the 6.2 Catty block and bigger and better heads I might just wait and get something better down the road. I haven't even owned the car long enough to remember the power it had

exSSer

Have you considered a LS2 402 shortblock? They're available from several vendors, all forged, for a reasonable price. This way, you can dish the pistons for any valve clearance issues, or compression values.

slowride

iTrader: (3)

I did, but this home built path is much cheaper using most of my previous parts. I'd like better heads if I went 402+ etc, etc. I can come close to $3k with the 383 using my old block. If I stay with a 347 I'd have less than $2k in it. Remember guys I just bought the car. It's not like I was planing on spending the extra coin right away.

freakynipples69

iTrader: (3)

Yeah I would possibly look into a ls2 402. It should be around the same price as your other opitions.

383ss

iTrader: (14)

yep, I built it back in 99 and ran it for about 4 years and 50k miles. i beat the **** out of that motor. I tried a ton of different parts combinations. I ended up breaking some valve springs, pulled the motor and found piston that was starting to crack. I built a 408 instead of rebuilding the 383. just looking for more power

slowride

iTrader: (3)

Did you see any excessive cylinder wear or have high oil consumption when you tore the old 383 shortblock down? I just want to know that the high SCR I'll end up with(11.8+) will be ok on 92 octane when combined with the right cam to keep DCR in check. I don't mind adding some torco or 100+ octane once and a while, but not all the time. It would suck to build it and only gain a few hp with some extra torque. If it would make at least 460hp/440tq with the right cam and old parts I'd be happy for now. Add a 90/90 later and maybe see 480hp/450tq or so.

slowride

iTrader: (3)

Just for the hell of it anyone want to figure out the old DCR with the stock engine and head/cam package I use to have? I get about 11.23:1 SCR, but different numbers for the DCR on all the different calculators I tried. My cam LSA is 114+4 so I didn't know if/or where to add that in.

slowride

iTrader: (3)

Anybody else have an opinion on the high SCR of my possible 383 combo? I'll probably use a cam in the high 230's to mid 240's duration on an XER lobe. I should be able to keep DCR well below 8.5(~8.2-8.3 with <.045 quench) even with the high SCR(~11.7). What about power over the 347? Keep in mind this a ZO6 with 3.90's.

slowride

iTrader: (3)

Well the 383 is finished and running great. No oil consumption, slap or anything of the sort. I used a Eagle crank, Compstar rods and Mahle pistons From Trevor at Texas Speed. With gaskets, bearings, ARP main and head studs, internals, everything with some extra little machine shop stuff to get everything just right I think I spent around $3500 (- $ from old parts sold) for the shortblock. The shop let me help out with little stuff and also let me use valvetrain tools to check my old heads for proper setup.

The eagle crank was just fine. Pilot bearing hole was right and journals were good. I used 1 over main bearings and polished the crank to get ~.0018 bearing clearance on the mains. I split a 1 over and standard bearing set with the shop to get around .0022 on the rods. Everything balanced up fine, but we were surprised that the Compstar rods were no better than most Eagle stuff in terms of QC. I would have saved $150 going with Eagle on center rods with standard bolts over the Compstar rods (which have ARP 2000 bolts factory). I'm not saying I rather have Eagles over the Compstars, but rather that in my application I don't need the ARP2000 upgrade and could have got by with the on center Eagles(even the standard offset rods would have been fine). I'll sleep better knowing the Compstars with the ARP2000 bolts are in the engine though

We Did a little extra work on the block to get the pistons out of the hole (~.018 off the deck), but I can't see it being hard to build a budgit forged 347 for well under $2k. I had a lot of the little stuff like double roller chain, ported/shimmed oil pump, heads, etc. I did reuse the LS6 intake for now (slightly ported) and CNC Heads ported large valve 243's from the old heads cam setup. I went with a Comp 238 243 XER cam on 114 stright up. I needed to keep the cam around those specs to get my DCR in the low 8.4 range as 93 is not offered everywhere around here.

I'm going to take it to the dyno soon and swap in the SVO 30's injectors for the stockers. Just getting some break in miles before heading out. The car also has LG pro longtubes w/ 3"cats, Borla quad tip stingers, Haltec cold air, Shaner TB and previously put down 445/405 through 3.90's and a older XE 232 236 cam with the H/C 347 setup. I hoping for ~470/440 on the dyno now and any more would be just icing on the cake. Future plans are a Fast 90/90 setup and a 100-150 shot

Just wanted to say without this site and some of the in depth tech searches I did I would have missed a lot of things important to building a LS1. I have a lot of experiance with other cars, but I just got my Z last March and it's been a quick learning curve. I feel I have cramed a few years knowlege into a couple months, but thats ok. Now I just need a 4" plus bore block, new heads, etc, etc. Well maybe in a few years

Trevor @ Texas Speed & Perf.

iTrader: (3)

Congrats on getting the new setup up and running Ed! Let us know how she does when you get it dynoed!



Trevor
Texas Speed & Performance

slowride

iTrader: (3)

Sorry Trevor, I didn't thank you for the tech support over the phone The prices are hard to beat and Texas speed is a great group of guys.

Trevor @ Texas Speed & Perf.

iTrader: (3)

no problem Ed! That's what we're here for. Try not to terrorize the streets of Waterloo!

Trevor
Texas Speed & Performance