Break down of motor:

6.0 block bore 4.03
Callies Dragonslayer stock crank
71cc L92 heads and L76 intake
PTM 90mm TB
6.125 callies rods
-15cc diamond pistons
CR is 8.5:1 on the 370ci

Turbo kit is a legit PTK with upgraded T80gts and .96 A/R

Tranny is a 4l80e and 3000 custom T/C
9'' moser will be ordered soon with most likely 3.50 gears

I have a full custom fuel system, ss baffled tank, -10 feed, -8 lines, rails, return, big external, etc. Also have a snow performance meth kit and A2W intercooler.

I originally had this motor built as a 408 but was scared of the back pressure that it would have caused with the turbo and didn't want to modify and updrade the turbo, downpipe, etc. Thought this would be a great match instead while spinning it allot higher. The exhaust is the ptk kit and couple into a custom mandrel bent 4'' exhaust all the way back. I may change the downpipe to a 3.5'' if there is room buit either way I will be running an electric cutout that I got. Its a 3.5''.

The stock crank drastically changes the cam I was gonna use. I was going to use the smallest of the bunch due to back pressure and limited to only about 6k rev limiter. Now with the better suited combo and another 1000 rev I thought I'd put in one of the bigger cams and leaning towards the second largest of the bunch now. This will mostly be a street car and not a DD. Trips to the track of course but probably not much but how knows that may change. With this setup will the 228/232 be too big for a street car in an auto and opt for the smaller. I know many make great power with small cams on turbo cars but my research shows me they like bigger ones even more. The more it makes N/A will be the more it makes blown if setup correctly. Thanks for the Help!

 

What head gaskets are you using?

Im trying to see how you are coming up with 9.3:1

Is the block decked?

 

Engine builder told me the deck was .016 clearance and head gaskets are .055 MLS

Sorry my bad, never even thought of that, lol. Stroke changed I just figured it out to be 8.5 CR with the 71cc heads and -15cc pistons. I am at work right now and my mind is somewhere else but not sure where? LOL

 

those cams look like they would work well on a s/c rather than a turbo

 

Thanks but if you are refering to a reverse split I DO NOT believe in them myself. I know that many have ran forward splits with great results on turbo cars. Some even run straight splits in which I'd consider long before a reverse split.

 

I'm doing a similar setup on my car currently. The cam I have that came with a kit I bought that was formerly on a 6.0 bottomend is a custom cam motion grind, its a 226/223 .575/.571 on a 115. He had great luck with this cam. With AFR 225s, this cam, ls6 intake, the hiflo kit that I bought from him with a PT76GTS, thru a 6 speed with 3.73s he went 10.93@141 running out of gear on 14 lbs of boost. The car also dyno'd 740/750 to the ground on the setup. I had my doubts too about split reverse cams, but you can't argue with results!
I'm hoping to run solid deep 10s with stock 317 heads and a th400 or 4l80e next season. I'm still on a mildly built 4l60e, tci 3500 and stock 10 bolt for a while so I'll be on low boost til I get some beefier parts behind it.

 

Ya, I am not saying that reverse don't sork and of course you'll have good results still, its FI man. I just think it could be better. I am not naming the shop but there is a few on here that have shown that the traditional, forwar splits have worked better than the reverse. Each to his own!

BTW, sounds like a nice setup, congrats and have fun. Hope the drivetrain holds up for awhile, I am there with you, lol

 

226/226 .585/.585 114

Made over 700rwhp with a 76mm turbo, 15lbs, 3" DP, and a safe tune. Made these number long before running into any back pressure issues. From what I have read in your thread you are building a nice and powerful street car. With a 6000rpm limit I wouldn't worry about back pressure issues so much. You will have plenty of time to worry about all that when you turn the boost up to 20+lbs.

Have fun with it. It sounds like a solid build.

 

I'd go with option 2. For a reference I'm running a S480 with stock cubes and a 233/239 on a 112. I don't have it running yet but will let ya know the results when I do.

 

So you are going to mill L92's? I would do custom pistons instead of milling a factory head on a boosted app.

 

Both sets of L92 heads are sitting there as is, I wouldn't want to buy some to just mill them and most likely I'll run the 71cc stockers. These are L92's out of the box which flow pretty decent but don't cost a fortune. I agree on the pistons but given the cicumstance that they are already like that and the cost, etc. I'd never buy some AFR's for exmple and start milling the **** out of them. I am jsut not sure about 8.5 CR, I'd really like atleast around 9 or so. I don't want it to be dead off boost and its mainly a street car so it would benefit from a bit higher compression. On the other hand, 8.5:1, I should be able to spin the 370 to around 7000 with close to what the turbo will boost to and with meth of coarse.

 

Thanks allot Josh, I hope it ends up a solid build. Allot of time and effort so far and haven't even started yet, lol Just researching and getting all the parts first while stuff is being built as well. I am not going for a race car or a crazy DD, just something as reliable as possible whenever I decide to go out and eat up some stangs and whatever else I can too This isn't one of those, 'I want a 1000hp and still want it to drive like stock' threads. It was jsut told to me once that the cam should be the last thing chosen in a combo and thats basically where I am at again changing it over to a 370 from a 408.

 

225/225 .581/.581 113lsa

made over 900rwhp w/ a twin'd 408 on moderate boost.

we've been over 800 w/ 348-370 motors on stock PCM.

 

My point was that I wouldn't run a milled factory casting on a boosted app out of fear of them being a little on the thin side.

I was going to run L92 combo too but I've got a ls6 intake so decided on pp 317's

 

Interesting, I was originally gonna go with the LS6 intake and 317's aas well but came across the L92/L76 setup and thought it would be better. I was a lil ify on the mill job too and was concerned but told not to worry about it. Thanks for your input I'll definetly take it into consideration. Looks like 8.5:1 CR as of right now, any takers on if this motor will be a dog down low with this compression? It would be better for pump + meth and high boost though I guess.

 

Thats one of the reasons guys like runnin afr's and other after market casting they are much thicker then oems. Who really nows how much it helps though.

Have you seen many L92/L76 boosted combos yet? My setup is very similar to yours iron 370 LS6 intake stock tb ported317 S80 but I will be using truck manifolds.

I have also been on the fence about the 408. Mine is a t6 flanged unit so could probably go bigger but why bother might as well just max this thing out.

 

Ya if you have a t6 flange I'd say run it, especially with truck manifolds too. See what it can do and you'll be easily able to upgrade the turbo it need be. Keep it 370, to run a 408 you definelty need a big *** tubo if you want to do it right. A 370 is a great FI motor and can spin it higher where the turbo's like to be. If you run out of steam all you need is a bigger turbo, but if you wnet 408 you need to rebuild the engine, upgrade the turbo and possibly the piping, etc. Should be fun!

Not many have run the L92/L76 but its starting to be more popular now and speed inc has done a couple I beleive. They pushed one to 18psi with no problems and think it was a 408 too.

 

yeah 370's love boost.

 

Yes they do, nothing sounds better than a whistle at high rpm's

I am really pointing towards 8.5 CR the more I think about it. I should be safe with pump and meth as far as this turbo will support on this engine within reasons of efficiency anyways. I am only conerned of it being a dog down low but it really shouldn't be that bad, plus it should build boost at a decent rpm anyhow. I am stuck on the cam, it pulls me from the smallest to the largest.......... back and forth. One second I say its a turbo, you don't need a bit cam. Than the next, well why not.......... the bigger the better. Its not like it should be too big right LOL It seems like many have great results with smaller cams but the guys running the big cams just don't chime in?

 

I think its more the last line you posted