Sorry I'm getting in on this a bit late. But, let me relate my experience
with my MGB.
Stage 1 - was a stock cast iron head modified by Sasco Sport. Ported,
polished, big valves. Installed on old engine with c. 272 cam. Best lap at
Lime Rock = 1:19.021 - 9/4/00 Fall Festival
Stage 2 - an early (#180) stock used Pierce cross-flow aluminum head on the
same engine with an additional 10,000 miles on it. Best race lap 9/3/01 at
Lime Rock Fall Festival = 1:13.481
Stage 4 - New 90% race engine from Fab-Tek with cast iron highly modified
5-port head, 290 cam, etc., etc. Best race lap at 2002 Lime Rock Fall Fest.
= 1:12.61
Stage 4 - Same engine with Weber 45DCOE replacing SU's. Best test day lap
at Lime Rock (in traffic) 1:11.00
Conclusion:
While Pierce heads may not be state-of-the-art, they are incredibly good
for an off-the-shelf unit. X-flow results are certainly going to be better
than 5-port. You can definitely run higher compression without knocking or
pre-ignition. One of the guys at Pierce told me they have an MGB with 3/4
cam, & twin Webers on their x-flow alum head puts out 198 h.p.
BTW, I have installed a Longman head on the new 948 cc. engine that I'll be
installing in the Turner. Won't be able to get to that until I return from
Watkins Glen & Collier Cup Race. More on that in the future.
Norm Sippel
'66 MGB
'59 Turner
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