I finally finished porting and polishing my 1970 351W heads that I received from Barry McDaniel. Thanks again Barry, these should run much better than my 77 302 heads. I had no idea what I was doing while porting these but it had to help. Even these heads needed help. I am hoping to get between 300 and 350 hp out of this engine. Will these heads be capable of that much HP? I hope this engine will be done in the next month.
I would have to guess about 12 - 14 hours per head. The worst part was sucking all the grit and dust!! I did it in my garage and dont have heat so when I put a mask on it fogged up my glasses so I couldnt use one. I hope it was all worth it.
I have been thinking about going with this cam. Comp Cams XE268H. lift - .509 int, .512 exh adv. Dur - 268 int, 280 exh Does this sound about right? Recommendations? 77 302 w/351W heads above holley 600 vac dual plane intake 4:11 gears on race day, 3:00 daily 4 spd toploader long tube headers will probably put about a 150 HP nitrous kit on later but that will be a while.
It looks like a lot of meat left on the exhaust side of the heads, did you do a gasket match to port your heads. If you are wondering what I mean by that, is did you put blueing ink on your heads and then bolt a header gasket to the head and then mark with a very sharp razor the edge of the gasket at each port. This gives you a ending point so you know how far you can go, you do this on both sides exh and intake. The tear drop looks nice and for being your first time at porting you should be very proud! Summit sells a porting kit (and video) that helps you get the most out of your port job and it really helps for those hard to reach places. There not a set of heads made that can't be ported to get just a little more the what the manufacturer gives you. Welcome to more horsepower then what you had, now don't get upset with me but you now need 350 chev 1.94 intake valves and 1.60 exh valves to get the most out of your heads. I have been racing with MaxFlow Motorsports for 4 years now and with all small block fords but the Boss 302 head flow is where you gain the most HP for your dollar. If it won't flow, you won't go! And that's a fact. As always just my .02 Terry Gates AKA Bossmav
I forgot, Call Comp Cams 800# and talk to one of their tech people and give them all the info they ask for, they can match a cam up for you that will be best suited for your needs. Good luck and keep us in the looop. Bossmav
Dont waste your time making the combustion chamber pretty . Any material you remove from there only reduces your compression ratio. Someone mentioned chevy 1.94 and 1.60 valve . That would be a great idea . I have bad news though . This usually scares new guys to porting heads . After the valve job is done and especially if you have to install new valve seats , you're going to have to go back in there and blend the seat from the valve seat ( just below it ) down to the port to make it work at its optimum . It looks like you did a good job to me .
Those exhaust ports were matched to the 1 5/8" tube headers I have on my car. If anything, you want the exhaust ports to be just slightly smaller than the header openings so that the exhaust gases funnel in and don't run in to a wall, causing reversion. In fact, I had to open up the gaskets with a hand grinder because the ports and header tubes were larger. Looks good Jim. Lighening is right, you'll probably have to do some touchup after the valve job. Just go slow so you don't hit your new valve seats with the grinder (that means no beer until after the job is done!).
Yep, I noticed that I would have to open the exhaust gaskets up a little so I didnt touch that part of the heads. Do you really think that I should go with the Chevy valves?? My cousin did that and had absolutely no low-end power. In fact, it ran like @#$% until it hit about 4,000 rpms. He had 69 351w heads with the chevy valves. He drove it for about a year and the head of a chevy valve came off and trashed his motor. I realize the power part can probably be attributed to the cam. I just hate putting any chevy parts in anything!! I promise no beer. (a little J Daniels might help though) If you all insist, I will put chevy valves in.....but if it breaks, you owe me!
It's not uncommon to put the Chevy valves in, but remember you have rail-type rocker arms. I don't know if Chevy valve will work with them.
That is what I was thinking. The rail type are non-adjustable and the valve stem difference would cause a problem. I dont think the performance difference would make up for what I would have to spend to put them on. These will just have to work the way they are....until I get a set of aluminum heads!!! For the $250 I have invested in the heads, I think I will be happy for a while. BTW....I un-shrouded the intake and exhaust valve by almost an 1/8th an inch and polished the chambers for carbon control, I dont think I removed enough to affect the compression noticeably. The increase in flow should make up for any loss in compression (I hope!).
