1972 Buick GS 455 Gears 3.08 posi Turbo 400 w/ shiftkit Stage 1 heads Stage 1 Intake Stage 1 Carb Stock Manifolds 30 over flat top hypereutectic pistons Fuel duals A/C Car PS Steering Pwr Disc Brakes Question, what cam would people recommend or had luck with, Lunati Voodo (Advertised Duration:262 int./268 exh) or the TA (Advertised in: 265 exh: 280)???? Or is there something better? Thanks for every ones help, you guys and girls have been great!!
strictly a street car and nice cruiser....needs pood vacuum for the a/c and brakes Hate to say it, was a Chev guy (BBC Monte Carlo and Chevelle), so first BBB rebuild?
Rob, cam choice really isn't all that different in a Buick engine other than the Buick stock head likes a split duration cam, more exhaust than intake duration. Also you need to match it to your combination. That includes compression ratio. read this, http://www.empirenet.com/pkelley2/DynamicCR.html If they really are flat top pistons, you'll also need to check piston to valve clearance.
The Hypers like these are barely flat-tops. They have 4 notches in them so they can be installed in any direction. If they are what the OP has. https://www.summitracing.com/parts/slp-h392ncp30/make/buick With 3.08 gears I'd go with the tried and true, generally can't go wrong TA 212. I'm sure you can nit pick into something else but with 3.08's and no converter mentioned(hopefully not the big car 13" factory 1600 unit) you are limited because of off the line launch. That Lunati doesn't look that far off from the TA. The exhaust lift is higher but the pistons I list should clear it. Idle will be slightly noticeable on either cam but should produce good vacuum in a 455. I'm sure somebody will get on here and claim you engine will "explode" if you install the Lunati. I couldn't figure out what TA cam you are referring to. Please list the P/N or at least the .050" specs. Advertised duration is almost useless since different manufacturers measure it at different lifts.
Is the motor built already? If so what's the compression, or what compression are you looking at if it's not built then? Those Hyper Pistons do not tolerate detonating all that well especially above low rpm conditions so if 380 to 400 hp will put a smile on your face stick to the small side of a Cam choice that will make Peak hp by 5000 rpm, and guide this Cam pick with one that needs no more then a 9 to 1 compression.
The motor isn't built yet, CR will be between 9-10:1 running (i assume with flat tops w/4 reliefs and 69 cc heads, correct me if i am wrong) I want this for the street, as the 3:08 gears a/c, pwr steering and power brakes cant handle anything to radical
Thanks Mike your right they have the 4 nothces....my bad TA Cam 212-455 STOCK 1.55 RATIO IN: .459”EXH: .470 DURATION AT .050 IN: 218 EXH: 230 LOBE CENTER: 112 Lunati 10960701 Duration at 050 inch Lift:219 int./227 exh. Valve Lift with Factory Rocker Arm Ratio:0.484 int./0.505 exh. Lobe Separation (degrees):112 Was going to run the factoring BS 455 Torque Converter, with the BS Tranny (shift kit installed)..... Your thoughts You guys are awesome and i appreciate ALL the input, want to do this right
As soon as I see the word assume, I can tell you you are wrong. You need to know, not guess. Your static compression has a bearing on your cam choice to keep the dynamic compression in the pump gas range, especially with your hyper pistons. As mentioned, they don't tolerate detonation very well. BTW, the same thing applies to Chevy engines. You need to know how far in the hole these pistons will sit, piston dish/valve relief cc, and combustion chamber cc (not published figures).
A slightly higher stall converter will just make the car feel a bit better. Since it's apart, you might as well do something better than stock.
Larry Thanks for your words of encouragement and constructive criticism "As soon as I see the word assume, I can tell you you are wrong. You need to know, not guess" If i was all knowing as you, i wouldn't be seeking guidance or advise. Perhaps i would suggest a little more courtesy and respect when dealing with people, it does go along way and empowers people to reach out to others who have learned and can pass n their knowledge in a manner that reflects the true spirit of these forms. Here is a nice quote "manners cost nothing" unlike building a BBB!
Rob, I can tell he meant no disrespect, that isnt Larry. However, sometimes "a blunt knife still cuts to the point"
Sorry Rob, I didn't mean to offend you and if I did, I apologize for that. I'm just trying to say that you have to measure everything. You can't guess if you want to do it right. I linked you to that Dynamic Compression Ratio article because it is important. It has a downloadable calculator that lets you calculate your static compression ratio, then calculate the Dynamic Compression for different cams. That way, you get a good match to let the engine be all it can be without getting into detonation on pump gas. You want the right cam, but to pick the right cam, you need accurate numbers. You can't assume your heads are 69cc, they might be more or less. Some pistons sit far down the hole, and even if they are true flat tops, they could still produce lower compression than you want. Figure out the exact Static compression, then pick a cam that gets you in the 7.5-8.0 DCR range for best performance. Hope that helps.
I like the 212 for what your describing too, but pay close attention to what Larry is saying. The most important spec here is one you havent mentioned, and thats compression height of the pistons. Like Larry points out, that dictates how far the pistons will sit in the hole - Everything else kinda is contingent on that, from deck height to cam to lots of other decisions.
I made an excel spreadsheet based on that article that Larry sent. I realize that there’s stuff online but making it helped me understand a lot. I also added a lot of Buick notes to the side based on stuff I’ve read here. I can share it.
