348 hi-horse heads-differences

[bubbletop61]

Hi guys! I need everyones collective expertise and experience on 348 heads.

In Alan Colvin's book he writes that the 3781147 heads and the 3758379 heads are identical castings except that the 1147's were
fitted with larger valves.

My question is whether the larger valves can be put into the 8379 heads? Are the ports the same sizes on both heads etc?
I know the 1147s use 2.06/1.72 valves, but what are in the 8379's?

Also I have read somewhere that on 409 type "5586" heads that the valve spacing is "wider" than that on the 348 heads. This causes a problem due to the bore size when used with the 348block, Is this true? Any one have any experience using 5586's on a 348 block at 030 to 060 O/S Bore?

Thanks in advance guys.
Gar:D

[fatride]

Castings are the same, 2.19 is the bigger intake size, exhaust is the same at 1.72. All 348 heads will accept the 2.19 valve. The ports are the same. I believe the 409 valve spacing would limit exhaust vave lift in the 348 bore. The secret is blending the bowl area under the valve after the cutting work to remove the tooling steps.:cheers

[bubbletop61]

Thanks Fatride
I am assuming that the 2.19 valves can go in any of the hi-horse heads for 348, or will they fit in even the low horse standard heads? Do you recommend making this change even on the 1147
heads? It would be a good way to get rid of some of the corrosion on the seat faces...I mean, I wouldn't fell like I was just wasting the money fixing the seats if my nostrils could get a little bigger in the process. LOL Because I don't have to put stellite seat inserts in the intake valves, the larger size would not pose as much danger of cutting through into the water jacket. Any thoughts on this?

After I posted last night I read a bit more and found that the 5586 head was in fact used on both the 348 and the 409 in 1961.
So from this I am thinking that the valve spacing would be the same all 5586 heads whether 348 or 409 application?????:confused:

Cheers:cheers

[Travis]

What about the 0817 heads? I think those use 2.06 intakes? would it be worth sticking 2.19's in there? These are going on a 65 409...

Travis

[Bungy]

I always thought the 1147 and 817 heads had larger ports then the 379s but I might be wrong. The 379 heads have 1.94" intakes and the exhaust is 1.66" 1147s have 2.07" and 1.72" valves. I also don't think the 5586 heads were used on 348s. The 5586 heads (1961 409) and 817 (lo-po 409) have 2.07 intakes and 1.72 exhaust valves. The 5586 heads also have larger pushrod holes for 3/8" pushrods. The 379 and 1147 heads have 5/16" pushrod holes. The 690 and 583 409 heads were the only ones with the large 2.19 and 1.72 valves (Z-11 too). Any of the w motor heads can be fitted with lager valves either 2.07/1.72 or 2.19/1.72.

[Va348]

Being a eng. builder this is what I would Do. Grind intake seat just to keep high as possible. Measure seat and cut down a 2.19 to fit it made be 2.07,2.08 or what ever. Big as a rule does nothing unless you do a lot work on runners. I have try all this on my flow bench and dyno. Like I never put 2.02 in Bow-tie sb head.I use 1.94 for about 2 valve jobs next time maybe 1.95 or 1.96. Most important is from seat to guide and narrow the guide. On the bow-tie sb we are not allow to do anything,only with valve grinding stones.

Hope I help you.

Dale