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Wanted to ask and get a little more info on this combination using these heads. Putting together a SBC 383. 4340 3.750 crank, 4340 I beam 6.0 rods and forged flat top pistons. I will be using a flat tappet cam, 2 barrel Holley 4412 Carburetor, not totally stock of course. Turn no more than 7000 rpm's. Looking at a bowtie 23* Intake for it. The heads have 2.08 intake valve and 1.60 exh valves. Are these heads a little much ? How can they be used, if at all on this motor or do i need to wait to build a 406.
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those will kill all kinds of low power and throttle response over the whole rpm range with a 4412
I wouldnt use them at all period, its racing not just burning gas and money going in circles.
put some vortec bowtie on your ft 383 and it will run great, angle and flat mill them and theyll run even better. they are the best head available in my opinion. -
SCD is correct , way to much head for that 2brl , I do a lot of angle milled vortec for these type engines , its kind of like a restrictor plate engine , the more compression the better with that 2brl......Comment
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Just needed some verification of what i was thinking. ThanksComment
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Just talked to a new engine builder today. Ask him about the vortec head and he did say it is the way to go. So i will be strapping them on and want to use a 4412 e85 carb. Good combo i hopeComment
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for your requirements , about good as your gone get......Comment
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Changed a couple of things. Staying with the same heads. Switching to a Holley HP 4 barrel 750 carb and a solid lifter cam. In. Lift .562- Ex. Lift .584. Lobe Sep. 106° In Dur. @ .050†259° Ex. Dur. @ .050 269°. Will be using 1.52's roller rockers to help the lift.Comment
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Still too much head IMO. Ran friends car once, 360ci 13:1 pistons 6" rod with same heads on 4 barrel alky in limited late once. Car was dog on starts and throttle response off corner. If kept momentum was ok but have ran stronger 355's with smaller heads that would walk all over that motor from top to bottom but I'm anything close to engine builderComment
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The 2.08 valve is better suited to 4.125 bores and more cubic inches. Depending on the combination, you sometimes find that the larger head will be lazy up to a certain point, then when the engine comes alive it is hard to control. Almost like a light switch.
A smaller head would make the best average TQ and HP and it is easier to drive all around . I think you are going to have a narrow power band with that combination. With a little work even the Sportsman II's work well on a 383 dirt engine.Comment
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we have 2.5, 1.6, 200cc iron eagles on our 383. awesome comboComment
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what are you talking about when you say 2.5 ?Comment
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I'm sure he meant 2.05 intake and 1.60 exhaust.Comment
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I have this combination now. ARP 4 bolt main and head studs in the block.. Scat 9000 3.75 crank, forged flat top pistons and scat I beam rods, 7/16 bolts. The cam will still be a solid lifter cam. In. Lift .562- Ex. Lift .584. Lobe Sep. 106° In Dur. @ .050†259° Ex. Dur. @ .050 269°. Victor jr. high rise aluminum intake. The heads are aluminum. 205 runners. 2.02 1.60 valves and using the Holley HP 750 DP.Comment
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That seems like a really long cam. Mine is only 241@.050 with basically the same combination.Comment
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That's alot of cam, and will more than likely be lazy on restarts and up off the corner. With that long of duration and duration split you'll be blowing your cylinder pressure right out the exhaust. But besides the 205 heads it would make power to 8,000+ if that's how hard you'd wanna turn it. I'd pick a combination and call Jones Cam designs or similar and get a cam specd to your needs.Josh K.Comment
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