superramvette

iTrader: (1)

Well I scored a darton sleeved LS1 block with a 4.1 inch bore the other day and am now ready to start my build. I am going to the machine shop tomorrow to see if the sleeves will handle a 4.125 bore which I suspect they will.

Okay here is what i have so far and I know these parts are not ideal but they are what I have and I am needing advice on this build.

I have the block, TSP terminator 203 CC (super small head I know this but it is what i have), new 228R cam (smalllll for a 427). I was planning on ordering a kit from Texas speed for the 4.125 bore that comes with a forged rotating assembly for around 2000 dollars. I do not want my car sitting around for any longer than it has to with summer coming up so I am trying to do this build for around 4 grand using the parts I already have. I figure I can swap the heads n cam later if need be.

I came across a deal on some pistons for a 388 using a 4.125 bore and stock stroke with a 6.1 rod. Would this be better for me to do since I am using such small heads and cam? Or should I big cube it now and worry about the topend later?

The car is a 01 M6 C5 with 1 3/4 longtubes, vararam, ls6 intake, full exhaust, 38 lb injectors. I have HP tuners with the custom operating system that can tune on the fly. TNT wet kit also.

I am not finding much for a 4.1 inch bore piston wise so I feel having it bored to a 4.125 is my best option. Any inputs and suggestions?

My goal is a very dependable driver, lots of torque and good street manners. I want it to be a low 11 second all motor car that puts a smile on my face.

Johnnystock

iTrader: (6)

228r for a 427!!!! Cant wait to see that!

superramvette

iTrader: (1)

stock ls7 cam is a 211/230 duration cam. I figure these heads will need the extra intake duration to fill the cylinders due to the lacking flow compared to ls7 heads. Very small I know but not smaller than stock. Should idle stock I would imagine.

COPO9560

If you are taking the block in, have it bored/honed to 4.125 and you can get normal 427 pistons off the shelf. A complete rotating kit from TSP could be ordered balanced and would save you a lot of time getting things right. A Darton sleeved block is an expensive piece and it would seem to me getting the short block done right the first time is the only way to go.

Have you considered selling your existing heads/cam/intake combination?? A set of L92 heads, LS3 intake and custom cam would be a far superior build. Used L92's are pretty cheap and LS3 intakes can be scored on E-Bay for around $300 with rails and injectors. These heads could be ported later on should you want more power.

DSRE

iTrader: (7)

definately put your money and time in the short block and stick with 427 or bigger you'll never be sad you went bigger!
i believe the darton sleaves can handle 4.185?
with that cam and those heads it will be a blast to drive on the street!
i'm guessing 430-440rwhp 475rwtq

superramvette

iTrader: (1)

i ordered the rotating assembly today from TSP. The problem I have is that my compression ratio will be 11.5 or 11.7(depending on head gasket) static and with that cam dynamic is too high. So I will have to get a custom spec cam for sure. My head porter is opening the chambers up to 62 CC and we are going to go with some bigger valves either 2.05 or 2.08 intake. I will see what I can do with these heads and just change the cam. According to him the edelbrocks have a lot of meat to work with so maybe he can open them up to make some power.

I did not have the assembly balanced due to I believe my machine shop can do it cheaper than what TSP wanted for the balancing.( I am having them assemble the shortblock)

I understand the l92 heads and will eventually be what I go with but for now a head change just is not in my budget.

So far into the build I have spent 2750(short block) and have not touched the machine shop bill, gaskets, or ARP main hardware or bearings.

mark21742

You should take a look at comp cams stroker cams (if in your budget)

I'm running 12.5:1 static compresson in my 408 with 57cc heads, but a 255/263 .624/.624 115lsa cam so my dynamic compression is back down to 8.22:1 and the motor has a VERY good street manner for the size of the cam due to the extra cubes....you might even went to look at the next size up (around a 255/267)

superramvette

iTrader: (1)

What kind of power are you making with that cam? How is the torque?

mark21742

Never had it on a dyno. I was running an a4 with 4,000 stall and it was an absolute beast.... Didn't get it to the track either, but we have lots of beautiful strait back roads around here and I have beat several sportbikes, the best one was a gsxr 750, cams, power commander and exhaust....the guy was shocked when I pulled on him and when I shut doen i had a good 5-6 car lengths on him.....lol I asked him how fast we were going and he said "no clue, I didn't look down at the speedo either". We laughed and talked for a few nonresidential then went our separate ways.

This year I'm trying to drop 1,000 pounds or more off the car, big rear tires, and swapped out the a4 for a 3speed manual