Victim of a bad build Need advice

1731 Views 6 Replies 4 Participants Last post by bruno, Aug 5, 2010

jonboyusmc

Discussion Starter · Aug 3, 2010

To make a long story short, I bought an unfinished project car from a young kid, that has turned into a nightmare. Basically I have an overheating motor with barely any oil pressure.

Here's what I have in it right now.
D1VE 429 block that I found chunks of hardened permatex going down the lifter valley return holes and a head gasket on backwards.
D0OE-R heads that have been decked an unknown amount
Pistons that were supposed to be 11:1 but turned out to be the low compression variety with the bath-tub size valve recess
Weiand stealth intake w/speed demon 750 also 2 stage nitrous set-up.
CompCam 270/280 dur .519/.520 lift.
MSD 6AL
MSD 8580 dizzy that had light silver springs and red bushing. Now it has heavy silvers with the black bushing. 14* intial timing 32* total timing

I'm tired of trying to guess whats wrong with my oil press. so I'm going to pull the motor and find out what's going on in there. Going to do the block oil mods, put a new hi-volume FRPP oil pump in and mic all the journals and bearing bores.

If the cylinders check OK, I would like to replace the pistons with KB hyper flat-tops with -2.5cc. This should get me somewhere around 12:1 CR, won't know for sure until I cc the heads and see where the pistons are in the bore at TDC.
I would also like to convert the carb over to E-85 to compensate for the increase in CR.

My biggest indecision comes in cam selection. Would a hyd. in the .600 lift and 280-300 dur range work for this,since I would be using a 100-150 total shot of nitrous, or would I end up being under carb'd?

Car will be mostly street driven with a few trips to the track thrown in now and again.

What do you guys think? I value everyones opinion on here.

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rmcomprandy

· #2 · Aug 3, 2010 (Edited)

YES ... it is not a good match in there.
Cam is probably to small, (what is its size @.050"...?), for the intake, compression is to low for the heads and the 750 carb is way to small for nitrous.

Given those mismatches there are many ways to go about correcting it however, it will depend upon the vehicle and how it is going to be used as to which is the best way.

What's it weigh...?
What is the rear gear...?
Auto, (torque converter), or stick, (Flywheel), ... ?
What tire size is going to mostly be used...?

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jonboyusmc

Discussion Starter · #3 · Aug 4, 2010

The car is a stripped down 94 Mustang GT. Its a race dash, 2 race buckets and no rear seat. No idea on the overall weight.

Rear gear is 4:10 now, but I would like to drop to a 3:73

C-6 trans with 3000 stall

Running 275-60-15 MT ET Streets for tires

I just found the correct cam info on Comp Cams site. http://www.compcams.com/Cam_Specs/CamDetails.aspx?csid=993&sb=2
Might be a good cam if I was going haul dirt with the car.

Thanks for the quick reply, I'm eager to hear suggestions from forum.

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bigblok86ranger

· #4 · Aug 4, 2010 (Edited)

Sounds like a mess I bet you are not gonna be happy once you tear into the bottom end. I would personally say if you want higher compression and to spray nitrous spend the money on some decent forged pistons. You might as well put some rods in it too. Zero deck the block and install Probe pistons P2404-30 pistons and a set of there H-beam rods. Randy or Lem can get you where you need to be with a cam. Intake would be good with a cam that has 240-250 [email protected]" But gonna want a bigger carb atleast 850 cfm. Put a 460 crank in it also just reread original post and noticed its a 429, but your piston selection will be much better with the 460 crank.

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jonboyusmc

Discussion Starter · #5 · Aug 4, 2010

YEP, it's a mess

The nitrous is just an option, because it's already there. The kid told me its jetted with 2- 150 horse shots. WAY more than I would ever throw at a stock bottom end. I thought the carb was too small. I just don't want to try and run a dommie on the street.

Randy, is there anyway to get this carb to flow up to snuff, or should I just get something bigger? When I get this all figured out I'm going to get with you on grinding up a new cam for me. I've been a machinist for 25 years, but I've never done any engine machining.

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rmcomprandy

· #6 · Aug 4, 2010

In your case I would change the crank, pistons and cam; (and whatever else you may need to replace worn parts), get around 10.25/1 compression ratio for pump gas, 13.5/1 for race gas.
You can live with the carb for needing great response and maybe you'll wish to put some good rods in it too.
That'll get you a well matched package where you can go bigger with the carb later if you wish.

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bruno

· #7 · Aug 5, 2010

good to met you the other night Jonboy

www.429-460.com
"HOME OF THE FASTEST BIG BLOCKS"

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