Hi,

I decided I want to shave the head on my 225L slant.
Previously the engine has been ported and polished. I'm not sure if anything else was done. + new elec igniton with dizzy etc, new coil, extractors, long runner intake with a 350 holley. After the head work is done I am thinking new cam.

I want to get the compression to 10:1.

I'm very new at this sort of thing so I want to get all the information I can possibly get.

Seems to me that the normal shave is 0.100? Has anyone done more etc?

With that do they rocker arms or anything like that have to be adjusted?

And also is there anything special you guys can tell me when I take the head off...?

Or anything you think I should get done at the same time...?


Is there any special tools that I will need?

And lastly does anyone have any cool stories to share...?

Thanks guys I know it's a lot of questions but I'm here to learn from the best!

cheers

On a street car/Daily driver 10-1 compression might be too high. a lot would depend on the cam. Bigger cam will allow higher compression, then a mild cam. Many racers have taken off more the .100, and even combined milling the head and top of the block, for up to the .200 range. You need to determine the use of the motor, and pick a reasonable CR for that use. Then determine (by measureing) what size combustion chambers will give you that CR. You can then cut the head to that CC's. While the head is off, you might want to shorten the valve guides, depending on what lift cam you plan on using, also if your cam requires dual springs, cut the spring seats. Definetley check the condition of the guides/valves/seats. Maybe do some pocket porting. Over size valves are also an option.

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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

You must measure the combustion chamber volume and piston to deck clearance to determine how much you need to mill to achieve your target compression ratio. I took .080" off a head to get it down to 50cc. I put that on my '67 225 with a Felpro head gasket and it's now a whopping 8.5:1, but with the stock cam it's about right. It was 8.0:1 originally. A '73 or '74 225 I tore down was only 7.7:1. You have to know where you're starting to know where you're going to end up. I took .100" off the block and head of my road racing 225 and had to get shorter pushrods.

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Joshua

Thanks guys, Your being a great help!

So I am thinking I will take the engine down to my local engine shop etc. and they'll be able to tell me exactly what I should do.

Being obsessed with engines, and also tight with money:P i want to do as much as I can myself.

Does anyone know what kind of power gains could be achieved just shaving a stock 225L, They start at 145Hp correct?

Thinking with my final setup that I might hit 200HP?

2bbl long runner 350 holley, head ported and polished, 10:1 compression, with new cam, extractors, new elec ignition.

Does this seem reasonable?

145hp stock is a poor joke. By the weight and 1/4 mile ET of my stock 1967 Valiant I was putting out about 80hp. Raising the compression to 8.5:1, ported head with 1.71"/1.44" valves, Holley 390 on an Offy manifold and 2 1/4" exhaust from the stock manifold to a Walker Dynomax Super Turbo muffler dropped my ET over 2 seconds (about 17.0 flat now) which equates to about 120hp. More cam and compression would make the car faster as would something better than a manual 3-speed.

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Joshua

If you want 200hp....
If you want to save money...
If you want 10:1 for the street...

You need to learn how to calculate static and dynamic compression ratios.

This can be done at home with cheap homemade tools and an online calculator. It is time consuming. ....for either you or a shop.

Anything else is guessing and will not result in 200 streetable HP.

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Yeah....Im the one who destroyed this rare, vintage automobile.....