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Discussion Starter #1
I have 66 lemans that came with a 326. The engine in the car is a wn c505736. It has 3 freeze plugs per side. The numbers on the distributor pad are a1f17 and below those numbers are 161 5D N, The heads are marked f171. I have been scratching my head trying to figure what engine I hve
 

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Here's the WN engine code options:

1967 400 265 HP WN M 8.6 254 142 1-2 7027066 Block Casting # 9786133
1969 350 325 HP WN M 10.5 068 48 1-4 7029263 350 HO Block Casting # 9790079
1971 350 250 HP WN M 8.0/8.2 (FB) 555 94 1-2 7041171 Block Casting # 481990
1973 350 150/175 HP WN A 7.6 555 46 1-2 7043062/63/72 Block Casting # 488986
1974 350 170/200 HP WN M 7.6 555 4C/46 1-4 7044269 Block Casting # 488986
1975 350 175 HP WN A 7.6 555 5C 1-4 7045269 Block Casting # 488986

The heads are date coded June 17th, 1971. The date code by the distibutor is a little funky. Should be structured the same as the heads(ex f117). If 7 is indeed the last digit, it's 1967 which would make it a 400. You can also check the block casting number by the #8 cylinder next to the firewall. If it is a WN '67 400, the casting should be 9786133...
 

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Yep. It's "cast" on the block on the firewall side of the cylinder. The very back cylinder.
Here's a pic... The top pic is the date code by the distributor. In this case a '69.
 

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Discussion Starter #5
Its a 71 350 with 250 hp. the casting number is 481990. I was hoping the it would be something with a kick to it. Since its a run of the mill 350,I might go with a crate engine instead of rebuilding this one
 

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you do know that you could but the cam and heads to make it a 350 ho, 68 i think it had 325 hp and 335 in 69 and there are stroke and bored pontiac 350's putting out around 500 horsepower.
 

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Take that 350 out to an overbore of +.030, add a 4.25" stroker crank, and you've got a 407 that still "decodes" to a 350 as far as anyone knows... it has possibilities :D

Bear
 
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