can i put the 351w heads on a 289 block. pros and cons, water jackets, compression issues, etc. I have the same size valves on the 351 heads as the 302 heads that came off the 289 block.

yes they fully interchange, the heads used throughout the years and on the different 289/302/351w motors are all interchangable... </P>


The only thing that my change doing a swap is the compression ratio, be sure you know the results before you do the swap, compression ratio may go up or down.</P>

Yes, you can bolt 351W heads on a 289/302 short block. However, there are a few things that you need to take care of for the swap to be successful. I know these things because I've done it several times and have learned the ins and outs of doing it successfully.</P>


1) You need to obtain shouldered bolts because the 351 uses larger diameter head bolts. These shouldered head bolts are the same length and thread pitch/diameter as the OEM 289/302 head bolts. Near the top of the shank, the shank diameter increases to match the diameter of the OEM 351W head bolts.If you use the smaller diameter 289/302 head bolts, the heads will walk around in the cylinder head hole and not properly tighten nor hold the head properly. If you can't obtain these special bolts, you can always have bushings installedthe cylinder head bolt holes to reduce their diameter down and allow the OEM 289/302 head bolts.</P>


2) The water passages between the 289/302 block's deck and the 351W cylinder headdo not match up correctly. The universal 289/302/351W headgaskets have allthe holes for both configurations. However, because of the mismatch of the block and head, you must drill the 351 head to match the block. Thisis easily done with a had drill and a 1/8" drill bit.You need to take an original 289/302 head gasket, place it on the 351W cylinder head and mark on the head where the there are not holes where the block has holes. The missing holes (5 IIRC)are near the cylinder heads outboard edge. Center punch where these holes need to be drilled. Then carefully drill into the cylinder head while angling slightly towards the obvious water jacket cavity. The hole will break through into the water jacket that is ~3/16 below the surface. If you fail to properly match and join the coolant passages between the head and block, you will suffer chronic blown head gaskets when you push the engine at wide open throttle.</P>


3) Because of the wider 351W intake ports, you should port match the intake you intend on using to the heads. The port heights<SPAN style="FONT-SIZE: 10pt; FONT-FAMILY: 'Times New Roman'; mso-fareast-font-family: 'Times New Roman'; mso-ansi-language: EN-US; mso-fareast-language: EN-US; mso-bidi-language: AR-SA"> </SPAN>are the same, just the widths are different. This port matching is not required, but it sure helps to get the most benefit from the improved flow that the 351W heads have over the OEM 289/301 heads.</P>


4) You may wish to have the heads milled to alter the combustion chamber volume. IIRC, the 289/302 cylinder heads have ~52 cc combustion chambers and the 351W has 58 cc chambers. This will obviouslylower the compression on the engine if no other modifications are performed. Just be sure you do the measurements and themath to determine what you need to do to achieve the compression ratio that you want.</P>


Good luck with the head swap if you end up taking on the task. I can tell you it is a very cost effective mod that is worth quite a bit of power increase. <IMG src=smileys/smiley2.gif border="0"></P>