Which one... 54 or 55 308?

blaine

I have the opportunity to put a 54 or 55 308 in my 47 pickup.  I hope to also put a Twin h setup on the 308.  Just wondering if there are benefits to using one vs the other.

40indianssgmailcom

Maybe a 200r4 or a 700r4 with the 308.  Would make for nice highway cruising with the o drive

blaine

Thanks for the feedback. Both engines need to be rebuilt.  But I plan to sell the one I don’t use.

blaine

Would one engine work better if I do go with a non-Hudson (e.g., GM transmission)?

GrimGreaser

They're the same engine, really. Did the 55's get the updates of the 56-7 engines? I have a 56 with hydraulic lifters and the greater '7X' valve clearance, that I put a 52 crank in to negate the need for the adapter between the engine and trans (Hydro)... I've heard the later cranks have a 'better' alloy - but I'll leave confirmation of that to those who know better than I...  the hydraulic lifters are nice since I have Clifford headers. If you get a trans andapter kit, just make sure the vendor knows what crank you have.

blaine

What about the intake/exhaust manifolds and Twin h setup.  I believe I heard that the intake has less air flow on 55.  And I think the air cleaners look different?  Not sure if they will fit on either year?

GrimGreaser

The later intake has an integral balance tube, the early intake may breath better.  Either exhaust/intake set will bolt on either engine. Final exhaust exit from the manifold may be different... Air cleaners are only slightly different and will mount on either set-up, too.  I had one of each when I got my Hornet.

ratlee2

You can run the later style twin H intake manifold as long as you run the matching exhaust manifold.  The outlet is angled slightly different, but works just fine on my 53 Hornet.

[Deleted User]

GrimGreaser said:

The later intake has an integral balance tube, the early intake may breath better.  Either exhaust/intake set will bolt on either engine. Final exhaust exit from the manifold may be different... Air cleaners are only slightly different and will mount on either set-up, too.  I had one of each when I got my Hornet.

Both the intake and exhaust manifolds are different on the 55/56 Twin H's.  Squirrel just went through this with his Hornet when the exhaust manifold broke.  The 55/56 intake has better breathing characteristics over the early ones with an external balance tube.  The balance tube was added to improve low/mid range drivability, and was kind of an afterthought on the '51-54's.  As Ratlee mentioned, the outlet angle is different on the later units.  The later manifolds are the ones preferred by experienced Hudsonuts, as they do develop a tad more power.  The earlier Twin H's were rated at 160 HP, the later ones 170 HP.  
 

blaine

Thank you all for the great feedback...

Can the twin H linkage from 54 be used on a 55?

54coupe

blaine said:

Thank you all for the great feedback...

Can the twin H linkage from 54 be used on a 55?

Yes, but you may have to drill the holes out to match the head bolt size.

blaine

Last question... I know some people use a 262 head for more compression.  Is a 232 head another option?  Better/worse?  Not sure if this relates to the 54 vs 55 discussion.  Maybe since the 55 has bigger head bolts.

54coupe

The 232 head will be too much compression for a car used primarily on the street. It will probably be OK at first, but after six months of daily driving, the carbon buildup in the combustion chamber, will cause it to ping. You will back off the timing to fix it, and now you lose power because the ignition timing is not optimum.... Ask me how I know. If you can get a good 262 head that would be my first choice. A 308 would be my second choice.

50C8DAN

 I have a 262 head available that was on my 308.

blaine

50C8DAN thanks for the offer.  I have one already.

40indianssgmailcom

If you decide to use the gm trans, the original column shift mechanism requires very little modification to use.  If you decide to go that way email me and I can send photos of mine attached to a turbo 350