454 400/330 swap
12-03-2006 | 07:58 PM
#22
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Joined: Oct 2000
Posts: 4,541
Likes: 107
From: Western Michigan
Re: 454 400/330 swap
Originally Posted by Crazyhorse
And yet again I have to slightly disagree with my esteemed collegue KAAMA. The heads of that vintage have flame-hardened exhaust seats and wouldn't necessarily need to have new seats due to a valve change.
The truth is that the seats will probably get changed because of installing larger exhaust valves, if not also because the seats are sunk so far down you'd need a rope ladder to climb down there.
The truth is that the seats will probably get changed because of installing larger exhaust valves, if not also because the seats are sunk so far down you'd need a rope ladder to climb down there.
Well anyway, we had some 049 castings off a pair of Merc 330's from a 1978 30' Scarab and we made the mistake of not installing hardened seats---at least we ignorant about it and weren't told by the shop that we needed to---maybe they didn't know at that time either??? So, we eventaully ended up with sunken seats and had to have them upgraded---live & learn. So because of our expereince with the 049's we had, I always thought ALL 049's needed to be upgraded with hardened seats when installing stainless valves. I have learned that when the later design "peanut port" oval port heads came out that the hardened seats already came that way as stock from the GM factory----but hey, maybe I am wrong on that one too!
By the way Cuda---lookin' MUCH better on that exhaust!!!
Last edited by KAAMA; 12-03-2006 at 08:00 PM.
12-03-2006 | 09:32 PM
#23
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Joined: Jan 2001
Posts: 3,140
Likes: 0
From: Holland MI
Re: 454 400/330 swap
Most heads that are out there and available have already had hardened seats installed in them. Most shops doing quality work would want to do it for a couple of reasons;
the seats are junk from being ground or just beat from running long hours,
to get the cc volume consistent and to get the spring installed height correct.
KAAMA, you've been around big-blocks way longer than me and have tried way more stuff than I have. Keep the information coming. We all benefit from it.
the seats are junk from being ground or just beat from running long hours,
to get the cc volume consistent and to get the spring installed height correct.
KAAMA, you've been around big-blocks way longer than me and have tried way more stuff than I have. Keep the information coming. We all benefit from it.
