ALright, a few of you saw my thread about picking a cam for a 383 with stock heads.

Well I just got a set of LE2 heads, so now I need to get a cam to go with it

big problem though.....

The machine shop that installed the 383 setup messed up.
I asked for 11.5:1 compression with the stock(54cc) heads.
They gave me +5 cc pistons(56cc LE2 heads) which according to my calculations will give me 13.5:1 with my .029 head gaskets, or with .049 gaskets 12.72:1

5.7" rods
3.75" crank
LE2 heads with 56cc chamers

Is there any way I can make this work? Or should i call them and see what they will do?
I guess there is a cam out there big enough to get the DCR down...
but will it be streetable? I use 93 octane around here

I think they thought I had 68cc heads or soemthing....

Thanks for any help!!

 

Okay, using .049 head gaskets and a GM847,
I seem to get a DCR of 8.83

Is that right?
4.03 bore
3.75 stroke
56cc
guessing .027 deck clearance until I can measure
+5 cc pistons

GM 847
advertised 296/304
112LSA 112 lobe centerline

 

You really want the thinner gasket to improve quench. As I understand from a lot of reading and good advice, minimizing quench is very important with 8.9 DCR. Are the pistons raised up (domed) or do they have valve reliefs of 5cc? I remember being confused about whether to use -5 or +5 for valve reliefs on the various DCR calculators. Double-check that.

If you really got the wrong pistons, get them swapped for the right ones unless you are perfectly happy with the end result. Tuning issues later due to too much compression with insufficient quench would be a handicap, so make sure that's not where you are headed.

 

I'll have to look if the are domed or have reliefs,
but they are speed pro H860CP30 pistons, which are listed as +5cc

 

Agreed!

Did you get the block decked? I went with 0 deck to create a 0.039 quench with my gasket. Didn't want to squeeze it more.

You need to confirm the volume of your chambers unless they have already been measured. For reference, I have a static CR of 11.3 and a DCR of 9.2 and have no problems with it. if you really do have such high SCR, my feeling is you would have to go with a cam with such radical overlap you would be unhappy.

 

I did not get the block decked.

Can anybody double check the my calculations on the DCR with a GM847?
I think running that would be fine.....

 

i looked those pistons up on ebay. they are flat top which would be -5cc. that should give you 11.5 cr.

 

ah......okay.
I get 11.71:1

Now to match a cam...

 

The crane cams are rated at .004" vs .006" for the comp cams so the crane cams will calculate out to having a lower dcr than the comp cams.

 

Does anybody have a cam suggestion for me?
I'd like to shift around 6500,
and its a daily driver, so I need some low end oomph

 

For a cam, I only ever tried one. I'm very happy with my LE3.2 cam, on a similar 383/le2 setup. Peaks at 6200, shifts at 6500-6600, and made 417 HP on Mustang Dyno, with a very flat 390ish torque curve. I have around 12.5 SCR. With your 11.5 you could use more advance than me. Mine was at 20* total for the Dyno runs on 94. I've since learned it can take more. With ~30* WOT on 93 octane, it pulled moticeably better up top but had 4-5* retard...so there is more power to be had. It's given me 12.0, and almost 119 mph, but not on the same run.

Search posts by me if you want dyno curves and more details.

 

you've got the LE2 Head package, why not just call up Lloyd and ask him about an LE2 Cam? If you wouldnt want to go that extreme talk to him about another custom grind to match his heads with a performance grind that will suit your driving. Brand name cams are great and all, but they didnt grind their cam for your setup. Talk to Lloyd.
http://www.eportworks.com/lt1.html
Good luck bro!