Folks, Need some insight or to hear what has served you well. Friend and I are about to get his car back on the road. Its a 1969 GS400 Stage 1 4-speed originally car but the 400 bit the dust 25 years ago or so. Its what he drove to high-school back in 83-84. Has special meaning to him and myself. With that said, he and I have raced this car on and off many years. With age, he's slowed down on what expectations are to be with the car but we need camshaft recommendations. Looking for cam that idles nicely, no vacuum issues, not a race car but has a little rump to it. He's going to reuse some old parts but the things of importance are its probably going to be a stockist build but the heads he and I used are cast irons that he ported years ago, going to use a performer intake, Holley 850 and some really early MT headers. Basically using a lot of what we already have parts but going to back off on expectations on performance but want some sound but not radical and reliability being of high importance. Any recommendations? About to knock the dust off mine and get back into the swing of things so we both can be more involved in the Buick community. Pic of mine in hibernation. Appreciate any help!
The first rule of Thumb with factory iron Heads and making Cam picks is that for every 100 hp you want the motor to make at the flywheel you need to run atleast .125" lift at the valve with .150" being even better! Example, 350 hp X .125 = .437" lift. Here's are some Intake duration @ .050" numbers in regards to minimum rear gear needs in terms of hot street use. 350 cid. 208 @ .050" 3.36 rear gear 400 cid 218@.050" 3.36 rear gear 400 cid 224@.050" 3.90 rear gear 425 cid 222@.050" 3.23 rear gear 425 cid 228@.050" 3.73 rear gear 455 cid 228@.050" 3.08 rear gear 455 cid 236@.050" 3.42 rear gear Note that if you are stretching things and wanting to run the bigger duration numbers you will need to run Rhodes veri lifters and go inbetween rear gear ratios to be happy with the out come! Note also that your always better in terms of great street performance and a wide power band to go with a better flowing / reworked heads with a tad bigger port volume to make greater power then over stepping the duration numbers of the Cam!
I was going to post my combo, but this thread has it and many others that should be relevant for you. (I’m guessing that what ‘y’all want, with what you have, should be right in that 12s to low 13s bracket). Patrick http://www.v8buick.com/index.php?threads/post-your-12-13-second-455-combos.314631/
I think you are right. With the engine in my car it ran a 12.1 and if I'm right he bought some WEISCO .038 pistons so his build and how it was assembled in mine is going to be pretty close to one another. Im not sure he cares how "fast" it is versus he want it to be functional, reliable and ultra streetable. For us to pick a cam that doesn't realize the potential of the other parts isn't important to him if its at the sake of, for example,resulting in vacuum issue to operate the brakes. He just wants the hint of sound of having a little bit of cam if that makes sense.
Static compression ratio is an important consideration in cam choice. If the pistons were bought a while ago, they will like sit a lot down in the hole limiting your compression. You really need to know exact numbers.
My current combo is about 9.5:1, all iron with Stage 1 heads and I’m running the T/A 290/94H. It’s quite driveable with a Hughes BOP20 converter. It doesn’t sound stock but isn’t staccato choppy. With headers he may want a little more duration. Patrick
I will get more information and update once I know the compression and all. It will be a 4 speed manual so selecting a convertor wont be an issue
I run the 290 94H too with the original M-21 4 speed. Stock small valve heads with a valve job and full length headers exhaust etc. 3.42 Posi rear. I really enjoy the car and like the cam. Sounds great but not too over the top for a cruiser. Only thing I’d change is the M-21 to an M-20. I’d like to build one and shelve the original matching numbers M-21.
Do you have a sound clip of your car? I'm building an engine and have the 290 94H cam and I'm curious what it will sound like.
Compression ratio is 12.5 to 1 *edit* 10.5 to 1 is correct, not 12.5. Sorry for the confusion Piston will be .010 in the hole.
12.5:1? Are they flat-tops with only valve notches? Whatever cam is needed won't be too smooth if you want to try to run pump gas with that compression. 12.5:1 is no way ultra streetable with a fairly mild cam unless race gas is involved. You need something like an old school KB C107 cam with that compression and they don't call it the "Window Rattler" for nothing.
You said the 400 bit the dust years ago. So what engine are you using? Another 400, 430, or 455? 12.5:1? Not sure how that's even possible without flat top pistons. You will need a fairly large cam to get the dynamic compression down if you intend to run pump gas. http://www.empirenet.com/pkelley2/DynamicCR.html
12.5:1 on iron and street is a bad bad bad idea. To get close to that compression flat top piston, almost 0 deck, skinny head gaskets and head chambers near 65 are need to get close. Are your math numbers right
TA C118 cam. With 10.5 SCR, DCR will be 7.8-7.9 depending on how far you advance the cam. Plenty of vacuum, decent idle but you'll know it has a cam. Want a little more sound? TA C113 cam, although that will push the DCR towards 8.2.
Yall are awesome. Sorry for the confusion. I wrote it down on a note pad correctly. Don't have any idea what I carried over here. Duh moment.
If you want the noticable idle and you're going with all the other old school stuff go with the C113. The 118 will have a barely noticable idle compared to the 113 and the 113 comes in stronger a couple 100 rpm lower than the 118. The 113 will really make those M/T headers sound off when just cruising around slow, like it has 10* more duration. My expectations would be that it could be a mid 12 second car depending on how well the heads are ported. The only reason I won't say lower 12's is because of the 4 speed. Hardly anybody wants to beat on a 4 speed car to get the absolute best ET's. If you really want to go old school I'd go with the Crane Stage 2 Blueprint. It would have 1* less overlap at .050" than the 113 but the extra exhaust duration to really set those headers a "tinking" even more. Either one will get people looking when you cruise through.
