383 To do list.. suggestions

[T16]

Could you please give me some upgrade suggestions regarding my 383 and drivetrain.. need a to do list for the wintertime

Here some info..

*383 bored .060.. makes i 394 cid i think
*Stock pistons with new rings..
*Stock 906 heads
*Windage tray
*Crower 271DHP cam
*Holley SD intake
*Carter ThermoQuad 800cfm carb
*Mopar electronic ignition
*Carter Street Super mechanical fuel pump
*1-3/4" headers

*Stock converter from a 400cid
*Stock rebuilt 727
*Stock 2.76 rearend 

Already on my list:
New converter.. With 2500 stall speed..?
New rearend ratio.. 3.23
Bought a set of portingtemplates for the heads..

Any more suggestions..? How about the valvetrain..? Maybe stronger springs.. Rocker arms..?

Driving the car now makes me a little disappointed.. when I floor it the tires wont spin. Yeahh yeah.. I know.. But its fun
Hope its the gears and the converter that is killing the 383 

[supserdave]

Do you know what your compression is?

[T16]

Do you know what your compression is?

I´m assumeing engine is pretty much stock inside.. flat pistons and 906 heads..
MAybe you guys can tell me..?

[supserdave]

What's your budget? Bang for the buck if you could afford the 900 bucks for the new aluminum heads from 440 source, that would be a great update, especially if your thinking about having someone else port the heads.

If you want to use your heads, maybe mill the heads and go to the thin steel gasket. Try and shoot for 9.3-9.5 to 1 compression if your not already there.

Right now the 3 main things killing you are gears, converter, and compression I bet. Otherwise it should run very well.

[Tom_440]

You could mill the block to zero deck if your flat tops are not too far down in the hole. Give this a read for some ideas:

http://www.moparmusclemagazine.com/techarticles/155_0209_383_engine_restore/

[Challenger340]

Be extremely diligent in regards to ensuring your intended Compression Ratio for your 383.

Read, investigation, learn, do whatever it takes, Pistons. Zero decking, WHATEVER,  to be sure you get around 9.3-9.5:1 C.R. with the iron heads.

No single factor, will affect the response & power in a "well done build", you can expect from the "wee-83" more than proper C.R.

Far too many people THINK they have close to the 9-9.5:1 mark, only to later find out that their "terd" is the result of 8.3:1 C.R., even with Flat-top Pistons.

Just my opinion, Bob out.

[firefighter3931]

Well said !

That HDP271 grind is an excellent cam and works great with 9.5:1 compression....pay attention to the details and you will be very happy ! 



Ron

[T16]

If you want to use your heads, maybe mill the heads and go to the thin steel gasket. Try and shoot for 9.3-9.5 to 1 compression if your not already there.

Well.. it´s a kinda low budget engine.. first ever engine i´ve restored. Basically just a quick "rewind" with bore honing and new rings/bearings.
Block was already .060 oversize. Will be running this engine for a couple of summers and try to build me another engine meanwhile.
So this winter i´m not looking for a complete tear down.. down want to change pistons etc.

Asuming my heads are untouched.. how much material can be removed..? Will I need new pushrods..?

When I get my heads of, I can calculate my compression. Of couse this should have been done when I did the assembly.. but hey I´m a newbie 

[Tom_440]

First measure how far your piston is down in the hole. Then you can determine your head chamber size to reach your intended compression.

[T16]

Ok.. assuming the 906 heads are 88 cc.. I´ve got 8.2 : 1 compression.
Also did a compression test before heads where removed. Found that the heads are in not so good shape.. Sellers told me they just got rebuilt 
Worn valve seats and guides..

Found a set of 915 heads.. that would bump up my compression to approx 9.3:1.. together with a steel gasket.
Altough they have the small ex. valve I think there will be a big difference..

[Ghoste]

Are you sure that it's a smaller exhaust valve?

[firefighter3931]

T16, go for the 915 closed chamber heads !  The cam you have is perfect for that type of build....the large split pattern on the HDP271 is designed for a stock head that has less than optimal intake/exhaust flow ratio. Bumping up the compression into the 9.3:1 range is an added bonus. ON a larger displacement motor (440) it might be worth installing the larger exhaust valves but on a 383, with that cam, you will be fine. The 915 heads are the solution to your head problems....get them ! 


Ron

[Rolling_Thunder]

915 heads rock!   

[T16]

Ok more questions.. got the heads.. they´re laying in my garage. Need som cleaning.. and then 

How do these heads respond to some mild porting (MP templates)..? Still got the templates for the intake valve.. wich is the same size as my 906.
Is it worth the job..?

And another thing.. Should I upgrade to stronger valve springs..?

Thanks 

[firefighter3931]

Ok more questions.. got the heads.. they´re laying in my garage. Need som cleaning.. and then 

How do these heads respond to some mild porting (MP templates)..? Still got the templates for the intake valve.. wich is the same size as my 906.
Is it worth the job..?

And another thing.. Should I upgrade to stronger valve springs..?

Thanks 

The porting templates are designed for the 2.08 intake valve & 1.74 exhaust valve. Unless you want to buy new exhaust valves then i would just leave them alone. It wouldn't hurt to have them looked over at a shop and maybe a fresh valve job done to them. If the valves are in good shape just reuse them and add a fresh set of valve springs. New valve seals too !

The Comp Cams #911 valvesprings will work fine with that cam. 


Ron

[T16]

Ok.. ended up with a set of 516 heads (1.74" exhaust) and a fresh Mira valvejob..

Problem is.. would like some more torque at lower RPM. 
Should I try another carb..? Maybe a squarebore..?

Dualplane intake..?

Or maybe engine need some tuning..?

[craigandlynda]

one more suggestion for some low-price insurance....put in the high pressure oil relief spring...easy installation, boosts pressure nicely

[Rolling_Thunder]

Ok.. ended up with a set of 516 heads (1.74" exhaust) and a fresh Mira valvejob..

Problem is.. would like some more torque at lower RPM. 
Should I try another carb..? Maybe a squarebore..?

Dualplane intake..?

Or maybe engine need some tuning..?

All street cars I feel should run a dual plan...    gives low end torque - where the 383 falls short in my opinion...   

[T16]

Ok.. ended up with a set of 516 heads (1.74" exhaust) and a fresh Mira valvejob..

Problem is.. would like some more torque at lower RPM. 
Should I try another carb..? Maybe a squarebore..?

Dualplane intake..?

Or maybe engine need some tuning..?

All street cars I feel should run a dual plan...    gives low end torque - where the 383 falls short in my opinion...   

Ok.. soo is it the Performer RPM that I want then..?

*edit*But thats not an spreadbore intake.. 

[firefighter3931]

The engine probably needs some tuning. Set the initial advance at 16* @ idle and map out the curve in 500 rpm increments and report back. Ideally you want 38* total timing at 2800-3000 rpm.

The SD is fine....for a little more throttle response you could add a 1in 4-hole spacer. I would throw a 3310 holley or Proform 750 vacuum secondary carb on it instead of the thermoquad. 

The stock 400 converter is not ideal for that combo but it should work OK. The glaring deficiency is the real axle gearing....it needs more gear, period. I would look at 3.55-3.91 for your car. 



Ron