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304 v8 head/piston interchange


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#1 acem

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Posted 28 December 2013 - 09:57 AM

I am tearing down a IH 304 V8 power unit (stationary engine) and the cylinders are rusty.  The motor sat for a long time.  I am concerned that the block may need to be bored if I use this block.  This engine has the 'pop up' pistons. I found another short block that has the flat top pistons but I don't think my heads would work.

 

 I am just trying to make sure I get all the correct parts.  Pistons and heads must match per piston shape.  Heads do not interchange between the 304 and 345.   Is this correct?  

 

Also what piston design is best for an irrigation pump engine running LPG?  There are no epa considerations here but I am very concerned about fuel consumption and longevity of the engine.  It runs 24/7 most of the late spring and early summer irrigating rice and soybeans..

 

I have a pair of IH service manuals (one for 815/915 combine engines and one for industrial engines) which are very helpfull.  Is there any good book that describes general rebuild, interchange, etc for the IH SV engines (266, 304,345,392).  I thought there might be such a book with all the scouts out there!

 

Thanks - Ace


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#2 73IH810

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Posted 29 December 2013 - 02:06 PM

I do believe you have to match the correct pistons with the heads in order to have the correct combustion ratio. It shouldnt be too hard to find a 304 for sale near you to use for the heads or even a better condition 304/345 to rebuild that doesn't have rusted cylinders. I see SV part interchange discussions frequently and it seems the 392 and 345 share more parts than the 304 does with either so you will be looking for 304 pistons if you rebuild your current engine. As for a rebuild book, the best thing I know of is a Scout II manual from IH. The engine rebuild is very well detailed and pictured. I went through my 345 with flat top pistons in my Scout following that manual religiously. The manual is still printed by Navistar, is very heavy and about $80. It covers 304 and 345 rebuilding since those were both Scout II options. Navistar may have a SV rebuild manual that is less, so check online or call a truck dealer. If you have any specific questions, I can look up anything in the one I have for you.
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#3 IHRunner

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Posted 06 January 2014 - 05:05 PM

266 and 304 share the same stroke. the 304 has an increased bore size. the 304 and 345 share the same bore size. pistons will interchange. call ihpa for parts. your local napa also carries a good selection of pistons as well as rockauto. the 345 is a bigger taller engine allowing for longer conrods. basically its a stroked 304 but a new block. the 345 and 392 share the same stroke. but bore size was again increased for the 392. info should be correct there

304 non emission has the dished pistons. later 304a has flat tops. dont swap heads. what a pain in the azz. either engine will run fine on lpg. no right or wrong there. ihpa and binderplanet have great detailed writeups of rebuilds. if you need any photos of the real thing just ask. i have a 304 and a 392 torn down in the garage as we speak...type....whatever

#4 oleman

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Posted 06 January 2014 - 06:55 PM

266 and 304 share the same stroke. the 304 has an increased bore size. the 304 and 345 share the same bore size. pistons will interchange. call ihpa for parts. your local napa also carries a good selection of pistons as well as rockauto. the 345 is a bigger taller engine allowing for longer conrods. basically its a stroked 304 but a new block. the 345 and 392 share the same stroke. but bore size was again increased for the 392. info should be correct there

304 non emission has the dished pistons. later 304a has flat tops. dont swap heads. what a pain in the azz. either engine will run fine on lpg. no right or wrong there. ihpa and binderplanet have great detailed writeups of rebuilds. if you need any photos of the real thing just ask. i have a 304 and a 392 torn down in the garage as we speak...type....whatever

The very early engines were a superior design to the replacement that was designed to meet smog.
The domed pistons and the matching heads sets them apart from the later stuff.
Disadvantage is parts availability for the older engines.
Starting in the late 60's the engines were smoggers where the New V345 produced less power than the 1960 V304.
IH totally ignored reality and rated all the engines at the same HP as the earlier ones.
The V304 was the most reliable of any of the SV engines and were the most widely used until smog took their power away, of course the rated HP remained the same.

#5 IHRunner

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Posted 06 January 2014 - 07:32 PM

just deleted my entire effing post,

 

basically i have both generations. in a stationary application you wont notice any differences. i use my terra for heavy towing. probably shouldnt but its small and agile and has plenty of power a holley 2300 and removing the emission hump from the head will cure the "de-HDing" that occured in the sv8's

 

a 304 in a terra pulling campers and car trailers and scrap loads wont notice a few ponies. in a loadstar im sure you're right. but any good mechanic can bring a 304 back up to snuff. silvolite pistons are avaliable. good cams. great bearings.





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