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I'm changing the old S1 150 short barrel for a longer later model 150 barrel on a small block S1 engine. Will I have to change the original barrel studs for the longer ones to accomdate? Cheers G

I have never done this conversion, but the external difference between the SI and later barrels is that there is one extra fin beneath the exhaust port (4) when compared with the earlier barrel (3).

This might help you decide if there is enough spare thread at the top of the existing studs to accommodate a longer barrel.

Knowledge wrote:I have never done this conversion, but the external difference between the SI and later barrels is that there is one extra fin beneath the exhaust port (4) when compared with the earlier barrel (3).

This might help you decide if there is enough spare thread at the top of the existing studs to accommodate a longer barrel.

Ah -- got it now -- I just saw studs online that were for s2 & s3 only -- that'll be the reason -- thanks for that

Or PX studs if you can't get the right ones.

CHRIS in MARGATE wrote:Or PX studs if you can't get the right ones.

Thanks Chris, I had spare studs in the shed and will swap them over now.

Knowledge wrote:I have never done this conversion, but the external difference between the SI and later barrels is that there is one extra fin beneath the exhaust port (4) when compared with the earlier barrel (3).

This might help you decide if there is enough spare thread at the top of the existing studs to accommodate a longer barrel.

Raises another question -- will I need to get a different cylinder head cowling to fit over the head and the longer barrel?

Granty wrote:

Knowledge wrote:I have never done this conversion, but the external difference between the SI and later barrels is that there is one extra fin beneath the exhaust port (4) when compared with the earlier barrel (3).

This might help you decide if there is enough spare thread at the top of the existing studs to accommodate a longer barrel.

Raises another question -- will I need to get a different cylinder head cowling to fit over the head and the longer barrel?

No but you may need a cowling packer from Darrell Taylor.

Scooterdude wrote:

Granty wrote:

Knowledge wrote:I have never done this conversion, but the external difference between the SI and later barrels is that there is one extra fin beneath the exhaust port (4) when compared with the earlier barrel (3).

This might help you decide if there is enough spare thread at the top of the existing studs to accommodate a longer barrel.

Raises another question -- will I need to get a different cylinder head cowling to fit over the head and the longer barrel?

No but you may need a cowling packer from Darrell Taylor.

Thanks for the info -- I'll check what I need when the cowling goes on - G