Detune 388 Stroker
Was looking for some advice on a cam selection.
Here is my current setup:
bored over .060
Speedpro powerforged flat top pistons with 6 cc 2 valve
Eagle 5.7" rods and forged crank
deck clearance .010
Felpro head gaskets 1003
Edelbrock Perf RPM heads 64cc
Comp 268XE cam and springs
Edelbrock Perf RPM intake with Holley 4160
Edelbrock double roller chain
Milodon high vol oil pump, windage tray, 7qt deep sump pan
MSD 6AL and Procomp billet dist
Hooker Header 1 5/8" with 2 1/2" Flowmaster 40's
79 Caprice 4 dr. TH350 built with shift kit, 2,000 B&M converter and 3.42 gears. The car weighs 3600lbs empty.
I am going to pull the engine and swap out the pistons to these:
Sealed Power #844-8-KH859CP60
383ci w/5.700'' Rod, Hypereutectic Pistons, .060'' Overbore
Piston Dia.: 4.060''
Piston Top: -12cc Dish, 2-Valve Reliefs
Pressed or Floating Pin
Comp Ratio: 10.28:1 w/58cc Heads, 8.65:1 w/76cc Heads
5/64'', 5/64'', 3/16'' Chrome-Moly Rings
These should net me right around 10.1 CR
I also want to change the came to the Comp cams XE252H. Will this cam work ok. I really want to de tune this combo as it is to radical and I want to just make a strong daily driver. I built this engine when I was a teenager and Hot rodded alot.
Thanks for your help.
honestly, I think you're going about it all wrong.
The engine you have is built to very mild specs. The only thing I'd look at doing for a daily driver is swapping to a good fuel injection system- it can really tame the engine.
A well prepped and tuned carb can come close to a FI system when everything is warmed up and you have consistent weather. But for ever changing real world conditions EFI makes a big difference in both mileage and drivability.
If it is in good shape? maybe a smaller cam and or what AP said.
I know the car is not tuned right. I have been messing with it for the last year and still don't have it driveable. I just dropped the tank and drained out all the gas as it was past its prime and causing it to blow white smoke.
Over the last year I rewired all of the underhood wires and installed the Procomp distributor to work with the MSD. I guess I need to start at square one on tuning. I know the distributor is in right. I have messed with the timing from 8* up to 18* and it is just rattling the valves not matter where it is at. I also put some octane booster in the tank but that didn't help either. The vacumn advance is working properly and I have tried ported and manifold source with no difference.
I feel like I have a timing issue of some kind.
What FI would you recommend?
BACK THE TRUCK UP!!! you're "rattling the valves"? what is that supposed to mean exactly? What gas are you running in it? BTW off the shelf octance booster isn't worth anything, so save your money.
It has real bad detonation when I try to drive it. Its a little beyond pinging. It runs fine while idling. I can accelerate it with no problems. Put it in gear and it just pings real bad. My dad always called it "rattling the valves" for detonation.
Dropping the tank is the right thing to do gas can go bad very quickly these days best to clean the system and start fresh. It can also pick up a lot of water.
Did it run any better. Whats the timing set at. Did you retune the distibuter and vacum advance/mechanical advance systems for high compression big cam? You should be able to run flat tops with Edel heads.
Have you tried pulling some timing out of it and a lot less advance and moving your vacum soure to a different port.
start with some fresh 93 octane or better and a spotless carb that is one size larger than stock on the jets. Set your timing to 12 base and 36 total and a slow advance curve. That should be a relatively safe tune to start with.
your compression is really high but it MAY run on premium gas if you get it tuned perfectly. Again, FI can help with that but it can't fix everything.
Start at the beggining, find true TDC with a stop, then confirm your timing marks at the balancer, get it advanced to app 14° to get it up and running. Make sure your vacuum advance is dissconected and capped. Worry about that later...assuming stock curve in your Pro comp dist with 14 initial it should be around 34° total, plenty safe with halfway decent gas. If it still "rattles" lets check lash, is it way loose and that's your noise? If the timing is confirmed correctly I would pull a valve cover and and check that as silly as it sounds.....
It does have fresh 93 has in the whole system. I have never rebuilt the carb. It has less than 30,000 miles on it, but has sat for the last 8 years started about once a month
I have not messed with the dist it is stock. I tried ported and manifold vacuum. The vac adv is not adjustable
Bygddy you mentioned the valve lash. I readjusted them last year. I did it while running with a half turn past zero lash. Now I'm wondering of I need to readjust them. They valve train is noisy but it always has been with the edelbrock valve covers
I would unhook the vacum advance and plug it for now. Then get the mechanical advance dailed in. Usally you need to limit its movement for higher compression engines and give them more initial timing. Also helps to smooth out idle a little.
Not sure about how the proform comes stock but most do not come setup out of the box for your setup. This is probably your issue. Also have you tried colder plugs or are you runing the stock style.
Ok will work on the procomp I think I have some lighter springs. On the plugs I am using autolite copper plugs that are 2 stages colder than stock. Thanks for all the advice guys. I am off on thurs and will see what I can do. I am getting ready to move it out to my mother in laws garage and bring my 64' stepside home to tinker with. If I can't get it drive able I am going to haul it on a car dolly.
very high compression and bad cam choice for the car. not reall good with a 2000 stall.
The distributor needs to be recurved. you need to shorten the advance curve to 10deg .
Then you can set the timing at 22 at idle and 32 total. Use a 4.5" rated power valve.
The comp XE cams are noisey at idle especially with any hi bleed lifter or hi energy lifter etc.
Crappy rockers don;t help.... use ported vacuum advance once the mech adv is corrected.
it will idle clean and not ping at WOT with modest 32deg timing. Thats about as best you can do with this .
You need this cam summit 1103 214-224-.442-.465 112 and converntional GM hyd lifters.
ok with high compression especially if you move it true "straight up" 112-112 centers when
you install it. Degree it in.... much tamer more civil cam ok with high compression ok with stock 2000 stall and 3.42's
better fuel mileage. quite at idle with good normal GM lifters. Check valve spring pressure. If excessive
the lifters will be noiesy er especially with XE cams.
uses a more stock timing curve.
You don;t need to rebuild the motor. not ever motor needs a hot rod cam.
The non adjutable distributor vac advance needs to be looked at and the rockers are suspect.
stock type rockers are fine with this camshaft and are quiet.
Engines do not ping at idle unless they are really really hot,, but the valvetrain may be noisey.
Is it detonation or valve train clearance noise? engine knock goes away with less spark advance,, valve-lifter noise does not.
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