What up guys Im in need of your input on this one.. Here is my situation.

Economy hit me hard so Ive had my car down for the last 3 years. I can now put together a engine and Im pretty much dead set on going twin turbo within a year. So I just gotta have this car out now , its been sitting too long and I really miss it! A LOT! Obviosly I dont have enough $$ to go head into a new engine and TT set up so I will build a really good N/a for now till funds are good for the step up.

End goals are mid/lows 9seconds on a full weight car with the same engine that Im about to purchase so I guess around 800rwhp or maybe a bit more. Gutting the car is not an option. It is a street/strip car

Currently I got full bolts including 92/92 on on the old engine. MWC rear end with 4.11s, Stock t56 (I might go 4l80e on the twins; well see).



I obtained a brand spanking new 215 trickflow heads milled to 61 cc for like $400 less so that is icing on the cake.

My options are as fallows:

Get a

1)-347 Stock Crank , forged Rods and Pistons with -3cc Valve reliefs

2)-383 Stroker 4340 forged crank,forged Rods and Pistons with -3cc Valve reliefs.

-both with Arp2000 and ARP Main

Both are good options and I would prefer the 383 since will have a little more Hp on the top end and a lot more torque.

The real problem and what is stopping me is in the compression these engines will have that would affect my future plans. Please correct me if Im wrong in my calculations and advice as with your previous experience what would be overall better.



The 347 with 0.40 gasket and the 61cc heads will give me a 11.04 to 1 (Great N/A SCR for the 1 year I plan on running this motor N/A) which when switching to 72cc and stock gm gaskets 0.058 will take me down to 9.32 to 1. (good and safe compression to run 93 oct). and is like $1000 less than the 383ci wich would push me into the TT setup sooner.

The 383 with 0.45 gasket and the 61 cc heads will give me 11.93 to 1 ( Awesome compression to run a big cam in the 244i-248e area) I could also go with a thicker gasket for 11.5 to 1. However when I go back to a 72cc and lets say 0.058 gaskets I get 10.19 SCR ( 317 heads with 71.06 cc = 10.30 SCR).

Now I really really, really, want to stay with 93 oct , I do have E85 nearby but here in SFL there are very few gas stations with E85 so going low on fuel 40-50 miles from home will be no so good.

Do you guys think that my goals of around 800rwhp possibly 12-14 psi would be very much doable on 93oct gas with the 383ci?

Any more details you guys need to help me out here just let me know .. Thanks a lot.

 

Come on someone has to have had experience running 10-10.5 CR and some 10-15 psi of boost??!!

 

I dont know much on the subject but Imy turbo builder said that he hasnt seen many good numbers on a FI 383 get an iron block and do a 402/408 thicker walls. 3.910 is about the max you want to go with an ls1 block

 

If you want to stick to 93....keep it in the 10's N/A and mid to low 9's for the boost. I'm in the same boat right now. Building the motor then adding boost later. I'll be at 10:1 while N/A and around 9.5:1 for boost. I might go down to 9:1.

Edit: I will be going forged 347 with a stock crank. Everywhere I read they are plenty strong for what I want to do. The 383 is really not that much more for the balanced rotating assembly from TSP but It just seems like more hassle and I want to keep my non boost mpg up.

 

Sell boltons and fast. Stock engine + turbo.

 

Bore will stay the same in both engines the only thing that will change on the 383ci is the 4.00 inch crank

 

THIS IS EXACTLY WHAT I WANT!! Man we must be twins or something. . That is my goal to run 10s NA and once I go turbo go low 9s with the same shortblock. I might end up going 347 forged as you are..

BTW check out http://www.thompsonmotorsports.net/p...products_id=11 .. Is the best most affordable 347 shortblock Ive seen with very good reviews , if I do end up going 347ci this is most likely the route I would go..

Any more inputs are apreciated..

Im dead set on staying aluminium since mine will have little weight reduction and these blocks are more than enough to handle the power I want.

Edit: Any more input is appreciated thanks...

 

I don't understand why guys want to run a 4" stroke on a stock block with. a turbo

 

No Im just looking for opinions what would be better for both stages, N/a and later Turbo I currently have the money to go either way so thats why.

right now Im leaning more towards the 347, is cheaper and will get me to both goals....

What are the disadvantages to going stroker and turbo? Im here for information so please if you care to share?

 

Less compression height weaker piston/ring pack

Pulling the piston out farther of an already short cylinder

 

383, 10.5:1, pump gas+meth, high 8's at mid 150's; pretty simple setup

 

10.5 to 1 347 with rods and pistons.ysi make 1k rwhp and running igh 150s on a bad pass.should mph mid 160s all with a stick

 

id hope a stick would mph