Intro and valve size question

Discussion of the 331-354-392 HEMIs.

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MAW
Posts: 21
Joined: Thu Sep 01, 2005 12:59 pm

Intro and valve size question

Post by MAW »

Hello all,

We're building a 331 Hemi for our 37 Dodge PU. My question concerns the valve sizes for the stock '53 heads. Can the later, larger valves be installed if the seats are opened up appropriately, and the larger hardened inserts added for the exhaust?

Thanks for any help,

Mark
392heminut
Posts: 488
Joined: Sat Nov 30, 2002 2:16 pm

Post by 392heminut »

Shouldn't be a problem, just make sure you use a machine shop that knows their stuff! :)
Last edited by 392heminut on Fri Sep 02, 2005 8:15 am, edited 1 time in total.
Owner of the Poor Man's Hemi Cuda
MAW
Posts: 21
Joined: Thu Sep 01, 2005 12:59 pm

331 HEADS

Post by MAW »

Thanks,

Wasn't sure if there was enough meat surrounding the valve seats for the 2.00/1.75 valves to be used. Even though I have a spare set of heads to work with I didn't want to see the water jacket staring back at me :D

Great site BTW,

Regards, Mark
George
Posts: 694
Joined: Wed Aug 25, 2004 4:12 pm
Location: Fl

valve size

Post by George »

the usual thing is to get 54 heads. Not only larger valves but bigger ports/runners, plus the use of the 4bl intake.
Bailiesdad
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Joined: Sat Dec 01, 2001 6:00 pm
Location: Maryland

Post by Bailiesdad »

You can get it all by using a set of truck 354 heads 1.94 or 2.0 intakes 1.75 exhausts, hardned seats, and sodium filled exhaust valves.... I think George just missed the 3 infront of 54 in his post....
MAW
Posts: 21
Joined: Thu Sep 01, 2005 12:59 pm

Post by MAW »

Thanks for all the feedback.

I assume there would be no valve/cylinder wall clearance issues with the 354 heads and the 0.200-0.250" larger dia valves? I was going to just clean up the bores, looks like 0.040 will do just fine.

Any ideas on what percentage of 331 block sonic test good for the 354 pistons if I choose to pursue this route? Any heating problems with blocks than have received this treatment.

Is there a reputable source for the 354 heads? I'd like to be sure they mag out good before buying and shipping cross country. Been burned on eBay quite a few times on parts that were claimed to be "perfect".

I can see this is going to turn into a case of "while we're here..." :D

Regards, Mark
George
Posts: 694
Joined: Wed Aug 25, 2004 4:12 pm
Location: Fl

valve size

Post by George »

If your'e new to Hemis you should get Tex Smith's Hemi Book from Hot Rod Library. There are differences between car, truck, ind., & boat Hemis. As in what & when things happened. One key part above was 354 "truck" heads. The truck heads are solid on the ends like the 51-54 car engines. The truck heads have the big valves. the 354 car heads have valves larger than the 331, but smaller than the truck or 392 heads. The truck heads have fat valve stems that dirupt flow, don't know if noticable on a street engine. There is a change in the size of the head locating dowel pins between 54 & 55 car engines requiring use of custon pins if you use newer heads. I don't know on trucks when/if change occured. If you got 354 car heads you could open the valves up, use the 392 water crossover & a dry intake. The '54 car heads bolt on & have the larger port/runners (example is the large oval exhaust ports vs. the small round ports on your heads) insall bigger valves & go!.
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