This is the second 383, the first 383 from SDPC didn't last very long. In any-case this engine is an all forged 383, with LPE CNCed lt4 heads, LPE LT4 ported intake, 1.6 rr, 847 cam, EM long tubes, with a custom dual 3 inch exhaust with an xpipe.

I'm happy with the results. The base tune was a mail order PCMforLESS tune, several tuning sessions by John Sealock at Woodbridge dynotech and fished by ED at automotive tech in Norfolk VA. Ed was able to eliminate a lot of the cam surge and he really improved the drivability. I extremely happy with the results.




the 426 number was the last pull on the sdpc motor before it broke and the 441 is the tuned engine I have now.

 

Very nice!!!!!!!! must be fun having 400+ at the wheel from 5K to redline!!!

 

just curious...what are the specs on the gm 847 cam?

 

Traction is an issue with 400rwhp.

Cam specs:
GM part number 12370847
Dur @ .050 = 232/242*
Lift with 1.6's = .575/.595"
LSA = 112*

 

Any idea what the heads flow? And what's the CR?

 

Head flow numbers are very close to these LPE LT4 heads.




CR is 11.2:1

 

[QUOTE=Bluewasp;1558284392]Traction is an issue with 400rwhp.
QUOTE]


Nice problem.........

BTW drag radials have worked well for me....so far I have avoided rain

 

My daily driver is past 400WHP, but it is not that bad.

Now my C4 is just rediculous. You can drive pretty normal with the occasional wheel slip (BFG DRs) but if you get into it and get more than a few pounds of boost, the tires just light up. This is tough at highway speeds as the back end tries to come around, always to the right. There is no reason that people "need" this kind of power, but we still "want" it.

Aaron

 

so what gives with the sdpc motor?why did it fail and did they do anything about it?

 

like to know that as well.

you have one strong 383 on your hands there. good job!


those heads arent far off my 195CC TFS heads. hmm!

 

I don't build engines for a living so I might be using some of the terms incorrectly. Please give me a little leeway here.

SDPC engine issues:
1. Engine burned oil. Lots of oil.
2. Block wasn't prepped correctly. Torque plate wasn't used and the cylinders deformed when you bolted a head to them.
3. They line bored the block and the center mains where .002 higher then the outers so the crank was bending/binding in the middle. Couldn’t turn the crank by hand, heads removed.
4. engine started to knock
5. high oil temps.
6. The cylinders weren't prepped correctly. As the piston left the bore on longer 383 stroke, the piston was damaged by the lower edge of the cylinder.
7. They installed a weak spring and the valves floated with the 847 cam. There was damage to the valve seats and to the valves if I remember correctly.

Coleman Racing engines in whitemarsh va rebuilt the engine and they did a much better job. Right from the start the Coleman racing engine sound better, and didn’t smoke. Idle issues went away without tuning.

I called SDPC and they said I had a 90 day warranty on the motor and he would get a manager to call me back but he never did. I was well past the 90 days but I only have a few thousand miles on the engine. I called again, was told I would get a call back and nothing of course. I even offered to pay for the return shipping from VA to TEXAS but they didn't care. In the end all the issues I had were because of a manufacture defective engine. The engine was bought fully assembled too. Paid close to $10,000 for the engine.

The rebuild ended up costing me ~$3500.00. New pistons, block work, crank repair, new springs, new valves, bearings, oil pump, rings, timing set, etc..

 

Rob, those are some of the best 383 #s I have seen. Congrats!! I was all set to pull my motor this week but decided to do a leakdown before I went to the trouble. All cylinders were less than 10%! So the motor stays for now. If you all get Jeff Creech up here, I'll definitely be up for that!

 

Are these 441+ at the wheel ??

 

Glad you're happy with it. Too bad you cant "see" driveability. No graphs for that. She made good power, and conservatively at that! Bryan Herter did a good job on the base tune, as it didnt take much tweaking down low to get it smooth under load.

 

thanks! I thought you had major issues with the engine? Sounds like everything is ok now.. ??? You could always drive down to Norfolk and have Ed tune your car. Send him an IM. edcmat-l1

 

You greatly improved the drivability of the car. Even on the dyno you pointed out how much smoother the car ran after the few changes you made.

Thanks!
Rob

 

I agree with Jerkyboy....those are amazing 383 numbers!!!

 

Not bad at all. The lack of peakiness sure is amazing for the LT series of engines....LS's do the same-almost makes them feel slow.

Minor point...the 847 cam actually has 234 intake duration at .050...I have been running the same camshaft for last couple of years-quite pleased.

Ground by Crane for GM...link here...

http://www.cranecams.com/?show=brows...tType=camshaft

Unfortunate to hear on the old short block-I was very tempted to go that route-they have a reputation of quality products...

 

Is the 363whp number in your sig with the 847 cam?

 

Very nice!

If you don't mind my asking, what was your total investment for this project, including installation and tuning?