That will be a good match. You should be around 8.4-8.8:1.

Lou

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Home of Slant6-powered fun machines since 1988

what kind of streetable hp can you get out of a well tuned motor keeping the bbd or holley 2280? with decent port work, a good ign(msd), free flowing 2.25 or 2.5 exhaust & normally asp. of coarse? and what cam and compression suggestions? ....... I have a 4 speed od truck. thanks

I was getting about 138hp at the wheels( 16.35@82 mph 3180pounds, 1/4 mile time calculator) out of my Valiant.
9.8:1, ported, stock cam, electronic ignition with GM HEI, clifford shorties Yed to a 2 1/2" pipe, Cherry Bomb turbo muffler and 2 1/4 " tailpipe, electric fan, BBD, 904 with stock converter, 8 3/4 3.91sg

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With flat top pistons and stock length connecting rods, how much would i have to mill the head to get 10.0:1 cr? Can I use pump 91 Octane with this config., or am I going to have to use fancy higher octane?

The engine is a '74 225.

It is impossible to tell. You need to take measurments. The motor in my 66 Valiant is 10.06:1 The short block is stock, the head is milled between .100 and .125. It already had one cut of a forgotten amount, and I had an additional .100 taken off. The chambers are 39 CC's, and a .022 steel shim gasket. As for the octane, it would depend on the cam and ign. timeing.

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Charrlie_S
65 Valiant 100 2dr post 170 turbo
66 Valiant Signet 170 nitrous
64 Valiant Signet
64 Valiant 4dr 170
64 Valiant 4dr 225