Headers for 351W

headers

The reason why most 289/302 headers will not work with the 351 is that the deck height is different and most 289/302 headers will not clear the floor support. If the crate motor you are planning on putting in is based on 289/302 your headers should fit. If the crate motor is based on the 351, then they may not fit if they are long headers. Shorties should fit for both although most 351 shorties have bigger primaries. I am running headman shorty 351 conversion headers on my '68. They fit pretty good.

I have a worn out 351W sitting on a stand that I'm thinking real hard about building into a nasty 393. My goal would be 500fwhp/420rwhp if I bother at all.

67chad said:

It is a 351 based motor. what size should the primaries be for a 357 with AFR 185's I am not looking to have tuns of HP I would be happy with 400. So it sounds like shorty's are not an issue in a 351 swap right?

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If you're just after 400hp, you could go either way on the header size. 1 5/8" will make more lower-rpm torque which is actually more useful on a street car(as opposed to 1 3/4"). Shorty headers are not usually an issue with Windsors. Longtubes for 289/302s have trouble being used on 351Ws because the collectors will hit the floor under the car due to the taller deck. If your shorties have at least 1 5/8" tubes, you could reuse them and just get the exhaust downtubes lengthened.

I forgot to mention that shorties also free up some space for (stock) power steering and stock clutch linkages. I have longtubes on my '68/302 and the z-bar goes between some of the primaries. I have to pull the z-bar to get the header out.