Hey Folks I'm currently building a 8b-a flathead for a friend and have a cam question for you. I have had experiance building flatheads before but have always run a stock cam cause I just love the low RPM Torque and the way they run so smoothly on the street. I've had very good results using a Stock cam and High compression aluminum heads. He has ordered a Isky Max-1 cam for this engine. Isky specs are as follows. 0.364 cam lift 0.350 valve lift 249 adv. duration 226 .050 duration It is a 8b-a stock stroke but bored .100 over with EGGE pistons. But He wants to run the Stock cast iron heads and intake as well. It is going in a Model A coupe that is just for shows and the street. Has anyone ever run a combination like this? Will the stock heads have enough clearance for this amount of lift? I know most popular aluminum heads advertize .400 clearance for valve lift. Will this thing be a Total Slug with this cam and the stock low compression heads? Also would you recomend an Aluminum Cam gear or will the stock Fiber gear be sufficient? Thanks in advance for any Advice you can give.
One datum point that surprised me... Go to Ford Barn and track down ordering info on JWL's "flathead facts," a bunch of dyno'ed and air flowed tests done by a guy who's an old racer and a pretty sophisticated thinker. He found (and was startled by) large losses of low end in a stockish 8BA. Just one test of one engine, but this guy does not screw up much. I believe I ordered my copy from the Van Pelt site. Book contains a lot of things to ponder. and...edit...on other stuff: Compression is good, for stock 8BA the EAB 1952-3 heads are smallest chamber, mill those to get tight maybe 040 piston clearance, work the valve pockets slightly if need to clear whatever cam you use. The '52-3 cams are also the hottest (though not really hot in any hotrod sense) late cams.
You will have to check the valve clearances with the heads once the cam is in. If you have to you can always have a machine shop clearance the valve pockets and mill the heads to raise the compression up. Just likes the guys used to do back in the dry lake days that couldn't afford alum. Heads. Stock intake will make the motor run but I think performance will be way down with a big cam and only one carb. I'd say get a stromberg 48 and jet it as big as you can. Big cams need fuel. And I would always run the alum. Timing gear over the fiber. Pm bored&stroked as he is a expert with flattys. He is super nice and very smart he can answer you ???s
Thanks for your replys! After posting this I decided to check the valve depth between the stock heads and an old pair of Offy's I had laying around. The stock heads measured roughly 0.350 depth while the Offy's measured out to 0.340. At first I was kind of shocked at this, but as the Offy's are vintage they may have been milled at some time or another. Judging from this Clearence should be OK, but I will still check once the cam is installed. Says he wants the stock intake and heads because thats how the car was run back in the day. The larger Bore should increase the compression a bit but I still have a feeling this thing is going to be sluggish at low RPM's... We shall see...
Try to find a pair of the old Weiand cheater heads. They'll look the part of stock but give you the umph. Sent from my iPhone using The H.A.M.B. mobile app
I used a Schneider Cam with a similar lift/profile. Worked fine with Edelbrock heads, so 8BA heads should have plenty of space. The cam pulls decent in my truck. Might be exciting in a lighter car, but not much lope if any. Sounds pretty stockish with maybe a little bit more growl.
i'd measure with that cam and iron heads. you'll be close on clearance. isky 77 cam doesn't have as much lift.
The EAB heads are very good heads better than some aftermarkets probably, Also check into a 1007- B grind cam. It came highly recommended by Pete and I had one in my 286 with EAB heads it was a great combination. Very streetable low and midrange power. here is an old link with a video of it running and some specs on the motor.http://www.jalopyjournal.com/forum/...ild-is-finally-done-and-running-video.726934/
Well He's already got the Cam and had the heads decked, so I guess thats what we'll run with. I'll double and tripple check the clearances just to be sure but looks like it will clear. We shall see what it does... Never know till you try, a little while back I put a 305 chevy together for a guy with just a summit cam and 4bbl and that thing runs like a scalleded Dog! Couldnt believe it always heard they were junk.
Tape some plumbers soldier pieces to the top of the piston about 1/4" long. Rotate engine over by hand a couple times with the head and gasket torqued down. Remove head and measure soldier. Ideal quench is .o40-.050. I would check that for sure if the heads have been surfaced.
I always use small aluminum foil balls to check clearance. Very important to get .040 to .050 clearance over the pistons. Makes for a more turbulent chamber and increases compression ratio.
I'm with Jack on this. Also, be especially careful with used heads; you never know how much they have been surfaced. Ask me how I know.
Ok thanks for the info! I'll be sure to check. Doesnt appear to have very much taken off. maybe 0.010 judging by the measurements of a known stock pair of heads.
If you can find an engine machine shop that was around in flathead days that did hipo work, they'll prolly have a fixture to set the heads up on a mill and flycut the valve pockets for clearance and if needed clearance for piston domes. Never actually tried it, but have thought several times about a single carb setuo using the 52-53 Merc manifold (4 bolt flange) and something on the order of a 4 bolt GM 2bbl. The '57 Pontiac had a fairly big one.
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