327 Build

[1972chevy]

I have a 327 small block bored 30 over, flat top 4 valve relief forged pistons, stock rods, stock crank, 60cc heads with 1.72 int. and 1.50 exh. 700r4 Trans, 27 inch tall tires, all going in my 1964 El Camino. What I am looking for is a street able engine nothing more than 350HP. Want to get ideas on Cam, Rear Gears, Carb Size, as well as possible up sizing the int. valve to 1.94 Not wanting to change heads out. All info appreciated.

Thanks

[jerry clayton]

working with any of the old iron cylinder heads from era before unleaded fuel-----unless you are working on a numbers matching restoration with all original parts, it isn't worth the time , energy or dollars to mess with the valve seat issues-------by the time you put hard exhaust seats you maybe won't have room to do the bigger intakes--altho at 1.94 x 1.50 aren't near as crowded as the 2.02x 1.600 are------you have many choices of economical replacement heads, whether in alum or cast iron versions there are lots of choices especially because of the spec racers out there--------

[firebird77clone]

X2 on the heads. Go to racingjunk.com and find a set of aluminum heads for less than it would cost to upgrade the iron heads. You might even be able to flip the iron heads to offset the cost.

You didn't mention the exhaust. Probably will need long tube headers.

Heads and headers are probably your greatest and cheapest power gains. You'll have to decide on heads before you select cam.

[Hurst01]

1972chevy,

Don't get your hopes up too much on getting 350HP using those heads. Modifying the heads to accept 194 intakes will cost a bunch and the heads were not designed for much flow. It would help to have head casting numbers, block casting numbers and the suffex codes from the pad on the right hand front of engine. Just taking a wild guess without knowing any of the above information, I would say you are in the 245 HP range as-is at best.
To go with a larger valve you would be money ahead to change out the heads for ones that have larger valves. To run in the 350 HP range you are going to have to use a domed piston with around a 11:1 ratio and heads with around a 2.02 intakes, aluminum intake, a very decent carb and a good cam.

[Hurst01]

Sorry, duplicate post.

[Mike P]

Sounds like a neat project.

Sorry, I know this is going sound like I'm piling on a bit. But lets start with the heads. 1.74/150, 60CC chamber heads sounds like you have 283/ 250HP 327 Power Pack heads.

Believe it or not I can understand wanting to use these heads, just for the cool factor and being able to say it’s original……but hey I’m the old fart who would rather look at the head marking that Chevrolet used on the end of the heads than see a set of aluminum heads stamped with Edelbrock.

I happen to be doing a nostalgia 283 and just did a set of these heads. If you’re going to use them I would defiantly recommend opening up the intakes to 1.94s,…..2.02s get a little dicey as I have seen some turn into junk by hitting the water jacket when opening up the runner. On the exhaust side you will want to have hardened seats added and will also probably find it needs a set of guides. If you are planning on running a cam much over .490 lift or 6000 RPM a set of screw in studs are probably also in order. Finally you will also want to have the heads milled a little bit to make sure they are flat. You will also find wear on the tips of the rockers so plan on a new set along with appropriate valve springs.

As far as the having 60cc chambers, that’s advertised and if the heads haven’t already been worked over chances are you will find they are really at 64-65 cc. AFTER I had my heads milled .015 my chambers all came out between 62-64 cc. I would recommend you also cc your heads after the work to see where you are going to be on compression so you when you do the final assembly.

I pretty much described what I did to my heads, by the time all is said and done the bill at the machine shop was pretty hefty (I’ve found machine shop prices vary a good deal from area to area so you need to ask first).

There are going to be other steps you may want to take when building the short block like finding out how far down the piston is and possibly zero decking the block etc.


As far as cam and rear gears, it will depend in large part on what you want the truck to do. If it’s going to be a street cruiser/highway car I would spend more time looking at advertised torque numbers than HP numbers and look for something that makes the best torque around 2500 RPM (chances are it will NOT sound very radical. If you want to take it too the strip and I would look at something more radical like the Comp cams 270 or 280 series.


The 700R4 is a good choice. Street car with a mild cam I would run a something in the 3.55 or 3.73 range. If you use a hotter cam a 4.11 gear set would be good.

Manifold would depend on cam and gears. Street with mild cam and 3.55-73, a dual plane intake……..bigger cam and deeper gears a good single plane.

You didn’t ask about exhaust but I’ll throw this in too. Street motor Corvette 2 ½” outlet manifolds (currently reproduced by Dorman), hot engine deep gears…. headers.


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