Thread: Got the rotating assembly / Now what heads?

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All the 400 / 383 discussion has made me dizzy. I came across what I think was a good deal on a 383 rotating assembly so I bought it. This is what I got for $669 including freight:

New cast steel crankshaft (unknown mfr)
Scat 4340 I Beam 5.7" rods 31CR5700P
190,000 psi rod bolts
Speed pro HE pistons H860CP
Sealed power cast rings
Clevite bearings
Fitted and balanced
Cam clearancing on rods

This is going in a '65 Studebaker Commander. I'm looking for 350-400hp and run on street gas.

What head size and runner size should I use?
Not looking to run high rpms (below 6k), probably want more low end that high end.

I've seen a set of Dart Iron Eagle SS heads with 67cc / 170cc runners / 2.02/1.6 valves at Performance Auto for $639 plus shipping.

What say you all??

Sound good, heads will work great. Top it off with a Proffesional Product dual plane cross-wind air-gap manifold and 750 vacuum secondary. ..... Oh yeah and cam XE268H from comp.
Check out the combo I used to run listed of carb sizing. Try for a compression ratio 9.3-9.8:1 When you get your machine work done on the block, have it decked to 0 deck height which is most times 9.0 , but to make sure do a mock up first and measure at tdc the distance between top of piston and the deck. You will need a piston stop and a staight edge and some feeler gauges. Sounds like a lot but the gains in performance are worth it. 0-deck clearance and a 0.039 head gasket makes plenty power and reduces chance of detonation considerbly. You can also polish the combustion chambers to help eliminate hot spots that lead to detonation.

I don't know the spec's for your pistons,watch out for compression ratio change with 67cc heads. Could easily go above pump gas range. Remember to also use a reduced base circle cam with that 400 crank. Hank

Originally posted by camaro_fever68
Sound good, heads will work great. Top it off with a Proffesional Product dual plane cross-wind air-gap manifold and 750 vacuum secondary. ..... Oh yeah and cam XE268H from comp.

I have a 750 holley v.s. and a comp 270H (I'm thinking of using a little small cam though, maybe use the Sealed Power CS274 I have).

Would a Street Performer intake be ok, I'm limited on height under the hood?

Originally posted by dcoffield
I have a 750 holley v.s. and a comp 270H (I'm thinking of using a little small cam though, maybe use the Sealed Power CS274 I have).

Would a Street Performer intake be ok, I'm limited on height under the hood?

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I'd stick with the 270H and the intake would be fine along with the 750 vs. That engine will perform great on the street and be impressive at the stop lights with stangs on side of you

Does anyone have a compression calculator that can tell me what compression I'll get on this?

Flat top pistons
383 ci
67cc heads

I just found some World S/R Torquer heads a little cheaper than the Dart. (67cc / 170cc runner / 2.02/1.6 valves / .550 springs / straight plugs / 3/8 studs).
$599 plus $70 shipping for the World heads
$639 plus $70 shipping for the Dart

Any thoughts on which is better or does it matter?

Originally posted by dcoffield
Does anyone have a compression calculator that can tell me what compression I'll get on this?

Flat top pistons
383 ci
67cc heads

I just found some World S/R Torquer heads a little cheaper than the Dart. (67cc / 170cc runner / 2.02/1.6 valves / .550 springs / straight plugs / 3/8 studs).
$599 plus $70 shipping for the World heads
$639 plus $70 shipping for the Dart

Any thoughts on which is better or does it matter?

The Dart are better. The Torquers are behind times. They were the pioneer when cast aftermarket heads came out but Dart has redone the combustion chambers intake runners to produce better swirl which promote hp and torque. The Darts outflow the torqers also throughout the lift range.

As for as caculating compression, I did your homework for you lol I looked up the part no. Those show 10:4 with 64cc head. It's not going to drop down but to 10.2:1 with those 67cc heads but I do believe dart offers them heads in 72cc that will be much more streetable.

Originally posted by camaro_fever68
Sound good, heads will work great. Top it off with a Proffesional Product dual plane cross-wind air-gap manifold and 750 vacuum secondary. ..... Oh yeah and cam XE268H from comp.
Check out the combo I used to run listed of carb sizing. Try for a compression ratio 9.3-9.8:1 When you get your machine work done on the block, have it decked to 0 deck height which is most times 9.0 , but to make sure do a mock up first and measure at tdc the distance between top of piston and the deck. You will need a piston stop and a staight edge and some feeler gauges. Sounds like a lot but the gains in performance are worth it. 0-deck clearance and a 0.039 head gasket makes plenty power and reduces chance of detonation considerbly. You can also polish the combustion chambers to help eliminate hot spots that lead to detonation.

A Zero deck height engine on the street is a waste of time and money.All the work and money for a little gain in comp. ratio.With this mild of cam Why?I.M.O. why not just take off enough to make it flat and then if you have any problems down the road you will still have some material left to make it flat again.

Originally posted by erik erikson
A Zero deck height engine on the street is a waste of time and money.All the work and money for a little gain in comp. ratio.With this mild of cam Why?I.M.O. why not just take off enough to make it flat and then if you have any problems down the road you will still have some material left to make it flat again.

erik, it's not a matter of gaining compression, it's a matter of setting the squish at 0.035" to 0.040" in order to suppress detonation. You don't have to zero deck the block to get there either, just use a thinner head gasket. For instance, if the piston was down in the bore at TDC by 0.020" to 0.025", you could still get your 0.035" to 0.040" squish by using a Fel-Pro #1094 0.015" embossed steel shim gasket. You don't have to start with zero deck to get there.

Although I've never done it, others have told me they have been able to run on pump gas up to 11.0:1 with iron heads and a tight squish.

Originally posted by techinspector1
erik, it's not a matter of gaining compression, it's a matter of setting the squish at 0.035" to 0.040" in order to suppress detonation. You don't have to zero deck the block to get there either, just use a thinner head gasket. For instance, if the piston was down in the bore at TDC by 0.020" to 0.025", you could still get your 0.035" to 0.040" squish by using a Fel-Pro #1094 0.015" embossed steel shim gasket. You don't have to start with zero deck to get there.

Although I've never done it, others have told me they have been able to run on pump gas up to 11.0:1 with iron heads and a tight squish.

He never say's anything about (the squish).I think you might of read to much into it.

erik, I'm gonna try this again. Here's your statement:

"A Zero deck height engine on the street is a waste of time and money.All the work and money for a little gain in comp. ratio."

I'm trying to explain to you that the zero deck height and 0.039" gasket are NOT to raise compression, they are to set the squish to control detonation.

Originally posted by erik erikson
A Zero deck height engine on the street is a waste of time and money.All the work and money for a little gain in comp. ratio.With this mild of cam Why?I.M.O. why not just take off enough to make it flat and then if you have any problems down the road you will still have some material left to make it flat again.

Boy, Boy, Boy, Had me fooled, making enough HP to bust 400 blocks, giving advice on everything etc.. and then giving me heat about my Big E huffer. Thought you knew what was up!!!

BUT THEN YOU COME IN HERE AND SAY THERE IS NO ADVANTAGES T0 A ZERO DECK HEIGHT ENGINE ON THE STREET. WOW.....

IT IS A GOOD IDEA TO ZERO DECK ANY PERFORMANCE ENGINE BECAUSE IT MAXIMIZES A GOOD QUENCH AREA TO PUSH THE AIR FUEL MIXTURE INTO THE CHAMBER, CREATING DRAMATIC MIXTURE MOVEMENT THAT CREATES A MUCH BETTER AIR FUEL MIXTURE IN THE SPACE OF THE CHAMBER ABOVE THE PISTON, AND TO TOP THAT OFF, A BETTER MIX OF AIR FUEL IN THE COMBUSTION CHAMBER CREATES AND ENGINE THAT IS LESS SUSCEPTIBLE TO DETONATION. THE SAFEST PISTON TO HEAD CLEARANCE FOR OPTIMAL QUENCH AREA IS .037-.039. MY SUGGESTION TO THIS FACT IS THAT UNLESS YOU HAVE EXTREMELY TIGHT TOLERANCES GO WITH THE 0 DECK AND FELPRO PERFORMANCE HEAD GASKET WITH A COMPRESSED HEIGHT OF .039


ERIK, DO YOUR HOMEWORK AND INVESTIGATE THE MATTER BEFORE YOU COME BACK ON ME AND HAVE A PROVABLE THEORY WHY I AM WRONG. ALL I HAVE JUST SAID HAS COME TRUE ON DYNO AND EVERYDAY DRIVING.

So, if I understand what you are saying (before the conversation got 'squishy' ):

I should get the rotating assembly, fit the crank and a piston to
be able to measure the height of the deck from the piston at TDC.

Should I do this after the block is machined and decked flat?
Then have the deck machined down to 0 when I have the measurement?

Do I need to use the new pistons and crank to check the deck
height?

Can this be done before taking the block in to be machined?

[QUOTE]Originally posted by camaro_fever68
Boy, Boy, Boy, Had me fooled, making enough HP to bust 400 blocks, giving advice on everything etc.. and then giving me heat about my Big E huffer. Thought you knew what was up!!!

BUT THEN YOU COME IN HERE AND SAY THERE IS NO ADVANTAGES T0 A ZERO DECK HEIGHT ENGINE ON THE STREET. WOW.....

IT IS A GOOD IDEA TO ZERO DECK ANY PERFORMANCE ENGINE BECAUSE IT MAXIMIZES A GOOD QUENCH AREA TO PUSH THE AIR FUEL MIXTURE INTO THE CHAMBER, CREATING DRAMATIC MIXTURE MOVEMENT THAT CREATES A MUCH BETTER AIR FUEL MIXTURE IN THE SPACE OF THE CHAMBER ABOVE THE PISTON, AND TO TOP THAT OFF, A BETTER MIX OF AIR FUEL IN THE COMBUSTION CHAMBER CREATES AND ENGINE THAT IS LESS SUSCEPTIBLE TO DETONATION. THE SAFEST PISTON TO HEAD CLEARANCE FOR OPTIMAL QUENCH AREA IS .037-.039. MY SUGGESTION TO THIS FACT IS THAT UNLESS YOU HAVE EXTREMELY TIGHT TOLERANCES GO WITH THE 0 DECK AND FELPRO PERFORMANCE HEAD GASKET WITH A COMPRESSED HEIGHT OF .039


ERIK, DO YOUR HOMEWORK AND INVESTIGATE THE MATTER BEFORE YOU COME BACK ON ME AND HAVE A PROVABLE THEORY WHY I AM WRONG. ALL I HAVE JUST SAID HAS COME TRUE ON DYNO AND EVERYDAY DRIVING. [/QUOTE WHY DON'T YOU GO BACK AND READ MY QUOTE.I NEVER SAID THERE WAS NO ADVANTAGE TO A ZERO DECK HEIGHT ENGINE.YOU CAN CHANGE HEAD GASKET'S OR COMBUSTION CHAMBER SIZES.WHY DECK A BLOCK WHEN THERE ARE OTHER WAYS TO OBTAIN THIS.PLEASE READ MY POSTS AND TRY AND QUOTE ME A LITTLE MORE CLOSELY.