I recently transplanted a 383 into my 85z that I predicted will make over 425 HP, but it is a DOGG! Here is a list of the build:

1970 014 2 bolt block
cast 400 crank
stock gm pink rods
zollner flat top pistons 4 valve relief
COMP cam XE284H 240/246 @50 ground on small base circle
Patriot Freedom aluminum heads 64cc 2.05/1.60
ProProducts polished crosswind intake 1500-6500 rpm
Mighty Demon 750 carb
1.52 stainless roller rockers
HEI ignition
Hooker shorty 1 5/8 headers, stock y-pipe with stock pipe open in rear no muffler

I bought the short block used with 400-500 miles supposedly. Disassembled everything and had the crank, rods, pistons, harmonic balancer, and flywheel balanced. The bores looked good so did the pistons so i did not have any machine work done, the block was already clearanced for the stroker. I installed new bearings throughout. The timing is set at 17deg initial and with mechanical advance it is at 37deg total(for now i have the vacuum advance plugged). The timing chain crank gear is on at 4deg advanced keyway. The engine startsup and idles fine and will drive good and sounds good but there is no power. I have a built 700r4 with 3000 stall, 3.42 rear. I have been questioning the cam advance because I never dialed it in. I have also been worried about how my intake and heads are matching up, the intake seems to sit low on the heads but is still a good 1/4 inch off the block, but even with a little mismatch I figured this engine would fry the tires which it doesnt. There is just no top end. Please HELP!! Any suggestions greatly appreciated!

 

Gator85383 - Can you post pics of the intake, etc..? I for one am a bit confused on what you mean by that statement. Maybe it is just me.
That engine should be making some power. Something is definitely wrong.

 

Hmm. I would say get a better intake. I have a proproducts intake on my car I enended up using a whole tube of gasket maker to get it to seal right. so you may have a vacume leak. I wonder about the cam advance becase most after market cams already have the advance built into them so the cam may be advanced big time... also check fuel pressure.
Good luck

 

My fuel pressure is wierd. Most of the time when i start it up the pressure is 10-12 psi, which I know is high, but sometimes it will drop to around 7 after revving it a few times and after it warms up but not always. I have a holley blue pump with the supplied regulator turned as far out as I can get it without the screw falling out. I am also running the stock pump inline before the holley pump, (Somebody told me the holley would suck gas through the stock pump, which it didnt). I should probably try just running the stock pump with regulator. How much of a pain is it to drop the tank and get that pump out?? What effect will high fuel pressure have?? Thanks.

 

The stock y-pipe choked 305s not to mention bigger engines.

You probably have other issues but a stock y-pipe is hurting you, especially on top-end.

jms

 

is your four barrels working properly? sounds like your only opening up the first two barrels.

this may help with your timing, its the old school way but it can get you really close.

with the car in park, rev the engine up to about 2500-3000 rpms.keep the throtle steady,turn your distributor until the car hits its peak rpm at that throtle position, then tighten the distributor. you might want to hold the throtle from the carb itself,makes it a little easier to keep at a consistant rpm.

 

I fixed my fuel pressure, I had the lines connected backwards. I think the intake is misaligned because when I was torqueing it down the blue ring around the inner of the ports on the gasket started showing above the edge of the intake. I pushed it down the best i could but there is still a tiny bit showing. But after looking closely at the heads the upper edge of the intake is only about an 1/8th inch from the top edge of the flat surface on the heads so i dont know. Is this where they should be?? Here are pics
http://www.putfile.com/pic/8138403
http://www.putfile.com/pic/8138607

 

doesnt look like a problem. just check for vacume leaks

 

Thats the biggest thing i see so far. also gotta check the tuning. Work that carb to make sure its getting proper fuel to the motor

When you say its a dog, what does it run? how slow is it?

Make sure the cam is what it is and 4 degrees advanced may be a bad thing since that cam should have 4 degrees ground in already when installed timing chain dot to dot

 

my pro products intake was retarded,,, the stud carb hole was so off the barrles werent even close to lined up with the two "ovals"

the ports were like 1/4 inch off from heads lining up,, etc etc.. check that just incase

nothing stupid like putting flat tappet lifters on a roller cam or anythign to do cam wise?

last thing is vacuum leaks.... check your air to fuel ratio and your timing for sure

 

I have the same cam and it says to install it 4degress advance like he did so I dont think that's the problem.

 

they probly say install on a 106 intake centerline which is 4 degrees advanced if its a 110 lsa cam, but comp grinds 4 degrees advance into the cam to begin with... So to install 4 degrees advance, or 106 ICL, you just put it dot to dot on the timing set... standard straight up keyway. If you put that cam in on a crank keyway that is 4 degrees advanced, the total cam advance is now 8 degrees and thats alot of advance. it would still make good power tho, but definately not to its full potential. your making that cam act smaller by advancing it.

 

what is the jetting in the carb.. if you say its the ones from the factory, CHECK IT.. make sure its what is supposed to be there.. when i got my annular 750, it had the jets for a downleg 850 in it.. a mere 9 sizes from what i'm using now.. motor bogged like no tomorrow..

and exhaust should be WAY bigger.. headers are pushing it.. it should have long tubes, let alone 1-5/8".. stock exhaust is MAX 2.75" which is what you could use for one bank of the engine.. go at least 3" single.. at 425hp, it could use more than 3" though..

that motor should be blowing off the tires till at least 45mph if built right..

 

Looks like im gonna be changing my cam timing pretty soon

 

hey everybody thanks for the replies, but ive been trying to locate a knock that has developed and after ripping into the oil filter I found chunks of bearing material. I guess its got to come back out and tore down. POS!

 

I WOULD DEFINETLY CHECK ALL OTHER THINGS FIRST FOR KNOCKS BEFORE RIPPING THAT MOTOR APART!! I KNOW FROM EXPERIENCE!

 

change the intake.the fulkie products are a hit or miss.i get to junk my toy becuase of the motor going to hell ,i wish you good luck though.