Which block to use?

hornet53

I've got two 308 blocks, one a '55 or '56 that is in my car and running good, and a short block (block, crank, pistons, cam, etc) '53 that is original to my car. The '53 still has the solid lifters. My grandfather swapped motors to get the hyd. lifters and found out later it wasn't necessary to swap blocks.



I'm contemplating doing a hot 308 build and was wondering which one I should run.



If I hop-up the later block, I'll still want some power out of the 53 for driving the Hornet like I like to do.



I guess my question is this; Which block is more receptive to power increases? Namely 7X type upgrades.



Either way I'll be rebuilding the '53 block first, but I'd like to know if I should start gathering the peformance stuff now or wait till the 2nd one.

Unknown

Your decision can be based on many variables, but one of them will establish the route to success... the condition of your blocks. Are they crack free? Are they bored beyond rework?

First and foremost is the need to carefully examine what you have before making any decisions about a course of action. Folks like Randy Maas and Ivan Z know the ropes of taking a standard Hudson engine to the next level. Take some time to communicate with those fellas and others who have chosen a particular block from which they will pull maximum horsepower.

Take a look at the information on my website... there is a wealth of history about Hudson engine building.

Good Luck.

Park_W

I'd certainly defer to Ivan or Randy as subject matter experts here, but my initial reaction is to go with the '55-'56 block. Already has the valve relief area that was used on the 7X engines, and an improved rear main bearing seal arrangement. Is it true that hydraulic lifters can be put in a '53 block with no little or no modification? News to me!

[Deleted User]

hornet53 wrote:

I've got two 308 blocks, one a '55 or '56 that is in my car and running good, and a short block (block, crank, pistons, cam, etc) '53 that is original to my car. The '53 still has the solid lifters. My grandfather swapped motors to get the hyd. lifters and found out later it wasn't necessary to swap blocks.



I'm contemplating doing a hot 308 build and was wondering which one I should run.



If I hop-up the later block, I'll still want some power out of the 53 for driving the Hornet like I like to do.



I guess my question is this; Which block is more receptive to power increases? Namely 7X type upgrades.



Either way I'll be rebuilding the '53 block first, but I'd like to know if I should start gathering the peformance stuff now or wait till the 2nd one.

Hi---I do not know how true it is, but I have been told that the 55/56 blocks are not as hard as the earlier 308s (not chrome steel alloy). Anyone know for sure?---Cliff Minard.

RL Chilton

hudson8 wrote:

Hi---I do not know how true it is, but I have been told that the 55/56 blocks are not as hard as the earlier 308s (not chrome steel alloy). Anyone know for sure?---Cliff Minard.

I heard this as well not long ago, but don't know for sure.



Regardless which block you go with, check for over-bore (could be sleeved, if necessary) and have the block magna-fluxed to check for cracks. Can't hurt and will save a lot of time and money if there IS a problem.



If what Cliff is saying is true, then you can't go wrong with the '53 original block. They really are harder than hell and are darn near indestructible.

hornet53

As far as I know, the '53 block was pulled solely to take advantage of the hyd. lifters. I'm moving back to where I have the '53 block stored in a few months. My plan is to strip it down and have it inspected regardless of where it ends up.



That's the first I've ever heard of the different alloy used in the later blocks. I've been running unleaded with no problems with the later block for years.

RL Chilton

Well, it's possible the later blocks weren't as hard as the earlier blocks, but still much harder than a brand-X block, hence, no need for hardened seats. Wish we had the true answer here, as my curiosity is now peaked.

[Deleted User]

On the Alloy used in the 55-56 blocks I have a partial answer.

When I built my 56-308 for drag racing I collected metal shavings from

porting & relieving the block and had it analized by a friend that works

at a major diesel engine manufacture here in Indiana.

The report came back that it was a hard chrome alloy but the funny thing

was the commits from the engineering staff at the diesel mfg. They were

all wanting what block this came from as they never used anything this

hard to machine. Once they found out it was from a Hudson 308 Hornet

block they were all supprised, especially when they found out the block

was cast in the 50's.

I did not have any metal shavings from a early block to test for a comparison

and really wish I had gotten some from ClutchGuy! All I know is that I went

thru quite a number of carbide cutters when porting & relieving this one.

I fully believe when Hudson & Nash merged a lot of things changed but

my 56-308 still has the same CWC casting house logo in it. Doubt that they

would change material since this engine was going out of production.

PaceRacer50

dougson

hornet53 wrote: »

I've got two 308 blocks, one a '55 or '56 that is in my car and running good, and a short block (block, crank, pistons, cam, etc) '53 that is original to my car. The '53 still has the solid lifters. My grandfather swapped motors to get the hyd. lifters and found out later it wasn't necessary to swap blocks.



I am in the process of tearing down a '56 308 which I bought because it incorporates a few 7X features. It will go into my '54 Hornet coupe. It has rough cut valve reliefs and the 1/2" head bolts instead of the 7/16" used on earlier (51-54) engines, which everyone says was a vast improvement, especially for performance use. I hope to reuse the hydraulic lifters and cam but I have never had any luck in trying to find out the characteristics of the hydraulic cam. They may be the same as previous mechanical grinds but the '56 engine had the highest hp from the factory of all the 308s, 174 hp. The '56 also had 12V ignition, a better rear seal arrangement, and improved cooling. The Twin-H manifold has an internal equalizer and additional vacuum ports so you can add power equipment. Oddly, my engine came with the earlier WA 968S series carbs. I plan to machine the block for 7X valves, hand finish the valve reliefs, use a surfaced aluminum head, and a Clifford header system.

Aaron D. IL

PaceRacer50 wrote:

On the Alloy used in the 55-56 blocks I have a partial answer.

When I built my 56-308 for drag racing I collected metal shavings from

porting & relieving the block and had it analized by a friend that works

at a major diesel engine manufacture here in Indiana.

The report came back that it was a hard chrome alloy but the funny thing

was the commits from the engineering staff at the diesel mfg. They were

all wanting what block this came from as they never used anything this

hard to machine. Once they found out it was from a Hudson 308 Hornet

block they were all supprised, especially when they found out the block

was cast in the 50's.

I did not have any metal shavings from a early block to test for a comparison

and really wish I had gotten some from ClutchGuy! All I know is that I went

thru quite a number of carbide cutters when porting & relieving this one.

I fully believe when Hudson & Nash merged a lot of things changed but

my 56-308 still has the same CWC casting house logo in it. Doubt that they

would change material since this engine was going out of production.

PaceRacer50

That's quite a story and testimate to Hudson's engineering. You should've told them they were milled from high grade "unobtainium" off an alien spacecraft.

If you get no other solid advice that's conclusive as to which block to use I'd use the '56. One would think it represents the highest level development that the 308's reached.