Settled on a 383....finally

[Mad-Dog]

After much debate and phone tag with the machine shop i have settled on a 383cid short block from Larry's Performance in Montebello,Ca.
Zero deck +.030" 4-bolt block, 6.0" rods, Keith Black hypereutectic raised ring pistons with a 19cc dish, 1/16" ring grooves and gapless oil control ring, Scat nodular iron stroker crank and Michigan 77 bearings fully assembled for $1455.00
Static compression is 9.6:1 with .041" head gaskets and 64cc combustion chambers, I'm using my cam 230/236-274/286-.490/.496" and Dart Iron Eagle
heads with 180cc intake runners, 2.02/1.60 valves and 64cc chambers.
Edelbrock Performer RPM intake, Proform 750cfm double pumper....etc, etc,
all the parts that are on the old 350.
Jim recommended a 2200 stall converter but I'm hesitant on that......

I'm hoping my 1 5/8 Hooker Comp hedders wont choke the new motor too much because i dont want to fool with the $400 exhaust any time soon...

 

[MTMike]

Sounds like an awesome powerplant

You'll love the torque that stroker makes

 

[trailblazr81]

Close to my motor except I have Air Gap intake and Edelbrock heads. I have the same cam and I went with TCI Sizzler. Its one step above stock, only extra 300-400 RPM and it works fine in my 73 K20. I had a 2000RPM stall converter on a 81 Blazer 5 years ago with 35" tires. Didnt like having to really rev motor when in parking lots or attempting slow maneuvers. My headers are 1 5/8 and they do fine. But definately go 2.5" exhaust. I was thinking 3" but I dont want to spend the $$$.

 

[Mad-Dog]

The extra long rods and raised ring pistons added $265 to the price but after the all the reseasrch i did on rod ratios i had to have them.
I actually sacrificed a bit of torque with this recipe but with the added dwell time the piston sits at TDC and the decreased friction from less piston rocking
this thing should really do the boot scoot boogy when i get her in.

 

[Mad-Dog]

My manifold is also a Air-Gap...forgot to mention that.

I looked at edelbrock heads before i bought the Dart's and could not justify paying more for a aluminum head that does not flow as well as the Dart's.

The present motor wants to push the truck now with the drum brakes when i am stopped at a light because of the high and choppy idle...i can only imagine how bad this problem will be with the 383 in there rumbling away.
(quick, throw it in neutral)

the current exhaust is 2.5" all the way back with Flowmaster #40's and a crossover pipe behind the transfer

 

[JIM88K5]

You will have less of a problem with a "choppy" cam when you increase cid. The cam will "look" smaller to the engine.

 

[SUBFAN]

Any power guesstimates from the builder?

That is a similar cam that I kind of wanted for the 400....

Look more closely at the Edelbrock heads. They have some that flow some respectable numbers. I too was a sceptic on them....

 

[icer97]

If you have the extra $$$ go for forged pistons over hypereutectic. I have almost the same set up but im running forged wiesco domed pistons, comp. solid .532 .555 lift cam, dart kool can intake, dart iron eagle 215 cc, 205 intake heads, and a 750 barry grant mighty Demon. It made 451 HP @ 6700rpm and 500 ft lbs of torque at 3700. What your building should be close if not pushing 400HP, and you will love it!

 

[Mad-Dog]

Around 425HP....maybe less maybe more

The 6.0" rod/raised ring piston combo has us both guessing....?

 

[trailblazr81]

My motor is suppossed to be 425-450HP. If I were to do it over again I would go with AFR heads. I think I got the Edelbrocks for a tad under $900 a few years back. Aluminum heads are cool!! But ya the cam seems smaller with more cubes. I have no problem at a stoplight. Idle is set pretty low. To where it doesnt seem to want to die with the 230/236 cam. I like it. And if you want to crawl slowly its kinda hard with a 2000+ RPM stall converter. Especially in reverse. On the street and while parking people look at you like you have a clutch and cant drive.

 

[Mad-Dog]

Oh yea............the AFR's flow like a river but i was very paranoid when selecting a set of heads and really wanted 180cc intake runners when i put the 350 together because i did not want to lose any port velocity at lower speeds.
I'm extremely happy with the Dart's and will probably stick with them even if i eventually switch to aluminum....maybe a pair of 215's with CNC porting

 

[jekbrown]

It made 451 HP @ 6700rpm and 500 ft lbs of torque at 3700.

yikes, is this for a truck? other than deep mud pit runs I can't imagine running my K5 around at 6700 RPM. I think the real question is, what is the hp/tq at 2000 rpm.

j

 

[Mad-Dog]

Ya dont need to with 500 ft lbs of torque at 3700......short shift at 4000 and keep on truckin....BEEP BEEP

 

[icer97]

yikes, is this for a truck? other than deep mud pit runs I can't imagine running my K5 around at 6700 RPM. I think the real question is, what is the hp/tq at 2000 rpm.

j

I built my truck for mud strictly. Its not much of a trail rig or street machine with a 3500 stall. Not to mention the $4.50 a gallon power 110 I burn. You cant hardly say what a motor will do with out putting it on the dyno. I gained another 20hp just by going from 36 to 38 degrees of total timing. Desk top dyno is suprisingly close however. If I was going to trail ride this rig or run it on the street I would of built a milder pump gas motor and would swap out my auto for a manual 4 speed.

 

[dyeager535]

How close was desktop dyno?

David Vizard found when testing that program, that actual dyno variation is a real problem, and one of the reasons that people can come up with different "real world" results.

It used to be on the website he(?) started, the article was free at the time, then the site went to all $.

 

[icer97]

Like you said there are many variables involved. But with my case the Desktop dyno was within 15 HP. The power curve and torque curve werent as acurate, but it will get you in the ballpark. You cant just read manufacturers est. HP add ons, they are usually way over rated. Example, my stock 5.3 puts out lets say 285 HP. So if I add Borla cat back exaust (10-15 HP add) K&N gen 2 intake (10hp) and a hypertech power programmer(up to 20HP add on) I should have 330 hp now right? Id say on a dyno you might see 10-15HP total with all those add ons. Its just funny when I hear around my town that Joe Blow has a 355 he built and its around 600HP. YEA RIGHT, I just laugh and say what ever.

 

[Mad-Dog]

Desktop dyno help

could i talk you into plugging my engine into the desktop dyno....?
383cid
3.75"
4.030' bore
6.0" rods
Keith black hypereutectic pistons
full floating wrist pins
19cc dished pistons
zero deck
.041' compressed head gasket
9.6:1 static CR
Dart iron eagle heads
180 cc intake runner
64cc chamber
2.02/1.60 valves
.74 intake/exhaust relationship
Edelbrock performer rpm air gap intake
Proform 750cfm double pumper 74 primary/82 secondary
Hooker comp 1 5/8" primary
2 1/2" dual with crossover
MSD 6AL ignition amplifier
230/236-274/286-.490/.490"-110 LSA

I would be vey grateful to you for this.....i hope i supplied enough info!

 

[icer97]

Well I cant figure out how to link the graphs and readouts to here. There are several things that cant be entered such as aluminum or cast heads, any type of ignition, size of intake runners, chamber of heads. The cam specs are entered by lift only, I dont have the updated cam program so its kinda vague. Im assuming this is a hyd cam? After entering all this I came up with 361 peak HP at 5000 RPM and 416 peak ft lbs of torque at 4000 RPM. It holds good power to 6000 but then drops quickly after that. Like I say there are many variables to this but usually this is on the low side if anything. It said my motor should make 439 HP and it made 451 so it gets you in the ball park without disappointing you by being a little on the low side. If I was to guess your set up after 6 or 7 runs on the dyno and some tuning by playing with valve lash, total timing, and maybe some metering block drilling on your carb, you should probably be making close to 370-380 HP or so. I hope I didnt get your hopes down with this, just my guess with what experience I have with the desktop dyno, and the real world dyno.

 

[icer97]

It made 451 HP @ 6700rpm and 500 ft lbs of torque at 3700.

I miss printed this, I dug out my dyno readout and it made 451HP@6200RPM, I usually shift around 6700RPM to keep my motor in its peak power range. My bad. I dont care what power it makes below 3500 due to Mr. 3500 stall converter.