Hello, If I have severly ported 69 windsor heads, which were done by someone who knows what they are doing, and a 4.62 gear, a c4 tranny w/ 3500 stall, would you use a 302 or a 331/347 and why? These heads will probably not have much torque because they were ported clear to the pushrod ports, and then sleeved. the springs are good to 550 lift easily. Intake manifold is a performer rpm, or I will buy a victor jr. I am thinking of using a herbert solid lift cam of 285/295 225/235 500/525 112 2500-6800 rpm.or 292/302 234/244 520/544 114 2800-7000rpm. or comp magnum 280 230/230 280/280 512/512 2000-6000 rpm.or comp x treme energy. 284/296 541/544 2300-6500 rpm. Which one of these cams would you use in which engine? This is a weekend only car, may see the track every now and then but it will be playing on the street every weekend. I was thinking stroker but from what I see the high revving 302's are doing just fine at hitting the 12 second range n/a. I may even use a little nitrous. I really appreciate and value the opinions of each and every one of you so bare with all of my questions please. Thanks in advance Steve.
The reason that I added the magnum 280 is because I already have one almost new, but I want to really rev with the 4.62 gear and the large intake ports. Thanks Steve
You ported the beejeebees out of them but you didn't mention if you increased the valve sizes and/ or unshrouded the valves in the chamber. Big ports don't do much if you choke them with small valves. Everyone has different opinions on this, but for strip/ weekends only I would go with the 347. "There's no replacement for displacement".
They were not ported by me, but yes they have either 1.90 or 1.94 intake and 1.6 exhaust valves put in them. Thanks Steve
RE If this is just a weekend toy i would run a solid cam , i would even if its a daily driver, but either way i would get a cam no wider than 110lsa. If you have the money i would build a 347 without a dought but a 302 will runs 12s EASY. But you might want to go faster later, so its up to you. The comp 282s would be a pretty good cam but i would look for something with more exhaust duration.
Darracq, Thanks for the info, I just think with the gear and the heads would like the rpm of a 302. Maybe a 331 also. Thanks Steve
Re just remember the stroke on the 347 is still shorter than a 350 chevy and they like to rev high. Lots of 350s with 4.56s and 4.88s. But factory heads arnt going to feed it very well. I dont care how much there ported.
I basically have the same heads you have , running in the mid 11s no problem I am using a 275/268 @ .050" cam around 600 lift . It makes no power under 5000 RPM . I would imagine you will need a converter that will stall at least 4500 to run the cams you mentioned . I also agree with some things mentioned by others . Dont bother running a hydralic cam and larger displacement engines are always the best way to go . If you run slicks on your car bigger than 29" you should consider running more gear reduction ( I use 5.13 with 30" tires )
Thank you Lightning, Which cam would you use in a 331/347? Do you think the smaller solid cam will be alright? Thanks Steve
Darracq, By saying do not get a cam w/ any wider than 110, do you mean not to go higher than 110 or not lower than 110? Sorry, I do not now all of these things yet. If I use a 106 or something like that does that make a stronger powerband (so to speak) that is shorter or would that smooth it out over a wider rpm? Thanks Steve
I like split profile cams for stock head motors as the peformance of the exhuast port is pretty dismal . I would not recomend a camshaft with a duration at .050 larger than 250 degrees . 110 degrees refers to how far apart the intake and exhaust lobe centerlines are apart in degrees Generally speaking , a smaller lobe separation ( 106 ) works well in cars with 4 speeds or large torgue converters big ( 116) with automatic cars with small converters . If you have a torgue converter that will flash at a higher RPM then the start of the engines powerband then I would recomend a cam with a centerline 110 also . Weekend street cars with duration cams in the 240 to 250 range perform pretty good but it is crucial you use either a four speed or a converter that allows you to use the power band . They would not be something you would drive to the beach with
Lightning, Thanks, if I have a 3500 stall converter, dont you think that I should be able to use a cam that will start making power @ 2800 or 3000 rpm. I believe I have decided to go with a 347 w/ the 5.315 rods and not the 5.4" rods. When finished I just want to be able to stay out in front of a 12.90-13.0 ls1 camaro. If not I will use nitrous.
Go with a 331, the Rod angles are better for the higher reving.. I like the look of the 1st herbert cam.. should make for a fun light to light trip.. AJ
Cams Keep the cam on a 108 or 110 lsa. I have had cams on 112 and they were a little slugish off the line with a 4000 stall, the cam was 248/252 @50 For a 347 i would look for a cam like 240/248 at the max solid and put it in 4 advanced, if you go that big. I can look though some stuff and find you a cam if you want me too. Your car will run high 12 without even tring.
