I was wondering if anyone knew, off the top of their heads, a couple things about my BBC. I have a stock 454ci out of a '73 Suburban. My questions are..... 1- Rectangle or oval port heads? 2- How much camshaft lift can I run with stock heads?(new valvesprings OK, don't want to tear it down though) 3- 2 or 4 bolt block? I'm not a BBC guru, so sorry if this stuff is common knowledge, I just don't know. What I'm hoping to do is pull this engine & th400 trans & put it in my '55 olds instead of the caddy 500 I had planned on. I wanna put a Comp Cams Magnum 280H(.520" lift), a gear drive, Torker intake/holley 4bbl, & some fenderwell headers & call it a day. I don't wanna tear down the engine 'cause it runs good & dosen't need rebuilt. I do want the thumpy idle that the 280H should have, & a 2000-6000rpm range should work good, though I'll probly never see 5000. Later- John
oval port heads 2 bolt main you should be able to run a .520 lift cam ok. But it probably needs guides and a valve job now....even if it runs ok....
more than likely oval ports. 280h no prob, might want springs gear drive - YOU'LL LOVE TO LEARN TO HATE IT. TRUST ME. Unless of course it is JUST a beer runner. 2-4 bolt? chances are 2. but who cares unless your running large boost or buzin to 10g's You might get razzed a little for the caddy bump, but I would go BBC anyday. Good luck. Consider a 10" converter if you do the Torker. Scoot
The caddy just needs too many things, & I have a whole running driving truck here to pull parts off of. Plus, even though theres been a huge spike in the caddy aftermarket from places like MTS, Torque Inc., Potters, & some others that escape me right now, theres still more available & cheaper parts for BBC. Actually, none of that is the real reason. The REAL reason is that I got these old Cal-Custom valve covers for a BBC. I gotta use 'em! They're SO cool!! Just joking, it's really a budget thing. So, back to the answers, thanks! Looks like some new valvesprings & away I go! Am I to be frightened of geardrives? Why will I love to learn to hate it? I'm scared now!! Thanks guys- John
For valvesprings get a set of replacment springs for a 440 chrysler police intercepter engine. It'll save you some $. You can run these with the stock retainers and rotators. I've used them in 4 or 5 engines with lift up to .550 and up to 6,000 rpm. The 280 cam may be a little big. That '73 engine is probably around 7-7.5to1 compression, and there's a chance it could have peanut port heads, but more than likly it has 896 castings. Jeff
Definately large ovals, get away from peanut port heads. It's common knowledge they outperform the high rpm only rectangles on the street. Like said above, if it's not been rebuilt it'll definately need guides & valve job, gaurantee you pull any spring off and that valve will be loose in the guide. This'll cost about 250.00-275.00 for clean & check, valve grind & 16 guides. Add around $50.00 for .003-.005 or so clean up surface cut. That cam you mentioned is old dead technology. New technology agressive ramp designs are the Voodoo cams by Lunati, they were designed by Harold Brookshire who is Ultradyne. He's an absolute cam genius. Look at Lunati 60201 , 60202 , 60203 , 60204 for BBC hyd. http://www.jegs.com/webapp/wcs/stores/servlet/product_10001_10002_756547_-1_10707 or if you want a solid flat tappet 60240 is awesome. (you'll have to contact Lunati direct for this one) You'll need springs with 140lbs on the seat (at 1.880) / 350lbs open (at 1.280 or so) for any of these cams. Comp Cams are junk in my opinion, run don't walk. And at very least old lazy technology. For lopey idles, closer centerlines. 108* extra lopey, 112* not so choppy but still sounds great. Less vac at 108*. 110* all have enough for P/B. Broader torque curve with 110*-112*. 108* LSA Voodoo's = Van Halen Hot For Teacher drum solo. The two most important numbers are duration at .50 and LSA. Stay around 235 @.50 for what you're trying to do. After picking duration and LSA , anything around .550 lift will be fine. When torn between 2 cams, always pick the smaller one, it'll drive better in town off idle to 4000. You'll need GM long slot rockers for just about any performance cam you install. Always check for .030 or so slot to stud clearance at max. lift. Don't buy crappy ebay roller rockers. And roller tips are just a waste of money. Comp Cams Magnum rockers are good, but expensive. Stock GM long slots are fine for what you're doing. Also new one piece 3/8 pushrods, avoid Comp Cams pushrods also. I've seen CC's tips broken off and mushroomed out like Elmer Fudds cigar. Your motor will have 5/16 pushrods with gunk inside, no good dirtwise or strength for a new Voodoo cam & lifters. Speaking of lifters, buy Lunati's lifters with the cam or Isky Red Zones. There are a ton of shitty chinese inferior lifters on the market nowadays killing new cam installs. Don't buy a bare cam then buy the cheapest lifters from somewhere else. Just add "LK" to any Lunati number and it's a cam and "lifter kit". Break any new cam in with Shell Rotella diesel oil and a bottle of GM EOS. You don't need a 4 bolt block. Everyone's routinely running 650+hp / 7500rpm and more on 2 bolt no problem. You said you didn't want to take it apart anyway. Forget the gear drive, you'll hate it in no time. Real engine guys think "gay" , when a gear drive rolls by, dummies who don't know cars will always ask what your funny noise is though. Forget the Torker, that's a single plane straight runner intake. They're no good for low rpm's and the street. Of course it'll work, but far from optimal, you'd be better off with a stock aluminum dual plane over a Torker. The hands down winner time and time again in HP gain, driveability and flow, in a hundred manifold tests is the Edelbrock RPM Airgap. With a Holey 3310 vac secondary. And long tube headers. You'll make 450+hp with this combo, with good ignition, tuned right. Of course that's all just my opinion mixed with facts
and swap some of those junk rectangle port heads on it and make closer to 500 hp (just messing with you...and wondering why so many guys think the big heads won't work on the street, they're great)
**MCQUEEN** is a BBC Super-Guru. That stuff needs to go in a sticky somewhere! I'll check out the Voodoo cams, I was just going with Comp 'cause thats what my Dad has in his camaro & it seems to work good in there(but his is the 292H). I had no idea the compression was so frickin' low on those, need a blower just to "need" regular 87 octane! So that means I can run it off dog water, right? I'm definetly not in the place to rebuild this thing right now, just getting it in the car is my main concern. I thought I could spend a little on a cam & stuff though. I always thought geardrives were cool sounding, a little whine sounds good. If theres a technical reason to steer clear, I'm all for hearing about it. I don't want something thats going to suck too bad! Thanks again guys- John
I'm no super guru. On the gear drive, whatever floats your boat, but make sure it's a name brand. A friend of a friend just had one of the cheapies come apart and tear things up. If you want to bump the compression some, it'll be a little more strain on your already old rings, but if it doesn't smoke it'll be fine. You can cut the heads up to .030 without have to cut the intake or intake sides of heads. That'll raise the compression about 1 1/4 points on a 119cc head (781). If you don't want to raise it that much or run close on intake rework, just have them cut .020 and forget it. You get a nice clean gasket surface, raise the comp. about 3/4 point and no worry about intake bolt up.
I'd suggest going easy on the cam, find something old fashioned with less than .500 lift, and lazy lobes, and hopefully the engine will hold together for a bunch of miles. not what you wanted to hear, I know, but......
I love this place, anytime someone says anything, there'll be some guy that'll go 200 miles and dig a hole 2 miles deep just to prove something different. Go over to Chevelles.com, major Chevy & BBC engine builders there, real world experience of street and strip performance laid out. Not a bunch of keyboard warriors. In Enginemasters magazine Chevelle.com is listed as a must read for anyone trying to build BBC's. Independantly, it's been my experience also that ovals work better on the street. I didn't say rec's were junk or wouldn't "work". If you're going to run 5-6K and up all the time they're the ticket. Search "rectangle street" , etc., and read on. You'll find after reading a lot, that most people have tried both & went with ovals over stock GM rectangles are more for race/wide open, and lazier in town and low rpm's than the more efficient oval 781 & 049's on the street. http://www.chevelles.com/forums/search.php?searchid=2286970 http://www.chevelles.com/forums/showthread.php?t=182264&highlight=rectangle+street http://www.maliburacing.com/patrick_budd_article.htm . .
Wasn't directed at you. Matter of fact looks like we agree. And didn't call anyone a keyboard warrior, just stating they aren't keyboard warriors at Chevelle.com.
The mid 1970's 454 engines were bad for compression. There may be a book out there somewhere that calls them 8 to 1 but cc the heads and check the deck height on one, it's disappointing. Keep it simple and mild until you decide you want to go through the bottom end. A valve job would be a very good idea. Don't let anybody tell you freash heads with more compression will make your rings go bad. That's total bullshit. If sealing the valves makes the rings pump oil and leak compression you needed rings before you did the heads.
You guys are overlooking the part about the engine going into a 55 Olds, he'll need an "rv" cam to move that pig....lol The part about the gear drive and dual plane I agree with but I want to know what rear gears he's got too. He needs some torque to move that car, that is unless he just wants the sound and the look.
Some of the truck heads have things called "rotators" under the exhaust valve springs. They're thrust bearings that allow the springs to rotate. If you want to use aftermarket hi-po springs and you have those, a machine shop can machine the heads to allow some solid spring seats to go in there in place of the rotators. It's not a very expensive machining job, but you have to remove the heads to do it.
I know that the hot tip is to use smaller port heads and fast acting cams and stuff. The thing is, we're not at chevelle.com here, we're at the hamb, and the hamb is about how we did things in the old days, and that means big ports, solid lifter cams with lots of overlap and not much lift, and 4.88 gears. And I've gone a hell of a lot quicker in a street car with rect port heads than I have in one with ovals
I installed a 1969 427 in my '72 C10 after I freshened it up. Performer manifold, stock pistons @ .040, don't remember what cam but is was for bottom end torque, studs every where, except heads. (Ever try to pull a head on the drivers side w/ power brakes and studs?). Predator carb, Mallory double life dist, MSD, roller tip rockers. The only problem I had was eating push rods and rockers. Finally called TRW Tech line and was told to put in L88 springs and 7/16 rush rods. Cured the problem and that was back in '85. Bottom line I guess is do the homework brfore you buy. God luck and good rodding!!!!!
I built a '73 454 a few years ago....it's in my '78 SWB....mild performance build. A cam from the Extreme line from Comp would be a good choice. I used the XE268....great cam, mild lope ,good power curve Specs here. http://store.summitracing.com/partdetail.asp?part=CCA-CL11-242-3&autoview=sku
Ok, heres a little more about my particular swap & what I want from it. I want a rough idle 'cause I like the sound. But I don't want to have a cam so huge it is a total dog, but am willing to give up a little on the bottom to get my idle. I have the problem most car guys have, if I even take the heads off I'll want them surfaced. Then I'll want a valve job "'cause they're already off" and then I'll be thinking that 1/2 a rebuilt motor is stoopid & I should go ahead & re-ring it, but why not spend a little x-tra & get some new pistons, wich is starting to look like a rebuild so why not get that $300 496 cast crank I read about in a magazine? The snowball effect. So what I was hoping to do is just put the used motor/trans in with a sprinkle of neat parts so it looks a little better under the hood & sounded good and drive it. Thats just what I think I can afford to do, I seriously appreciate all the info! I'm looking at one of the Voodoo cams, the 60204 2200-6400rpm range. I have 3.23 gears. Might try a mild converter. Gotta check on those "rotators", I might not use a big cam at all if I have to pull the heads. Thanks guys!- John
Do yourself a favor and put some compression in the motor. Personally I do not like this swap but If you are going through all the trouble of putting a chevy in an olds why not have it run decent? These ultra low compression big blocks are hard on fuel and do not respond nearly as well to cam changes etc. as a motor with at least 9.5 compression. Squirrel I agree with you 100% that the rectangle port motors of old would smoke the oval port motors on the street or strip. I also played with both.
I have a set of Corvette closed chamber square ports, and they are right where they belong -- on the shelf. Bob
i ran that cam (280D/.520L) with oval port closed chamber heads and had good results. drove it for a year and swapped to a bigger cam. the Comp Cams magnum was plenty and sounded good. i also swapped out the heads for a set of Merlins.... it breathed a lot better but for the money I should have just gone with rectangle ports... upper rpm's are limited with oval ports.
You will need more gear to pull that barge with a BBC. They are not a torque engine and you are building a higher rpm engine. put in some 3.73's and feed it or put in a torque monster like the caddy,455 olds,430 buick and get the power you feel and reliability CHEAP.
what? BBC isnt enough torque to pull a suburban? whatchu smokin?? Having built a warmed over 455 Olds in the past with a friend, they aren't cheap.... big inch Cadillac, Olds, Buick and Pontiac are not *cheap* alternatives. They are excellent alternatives but not cheap as you claim.
This thread is eligible for AARP. FWIW, closed chamber heads shroud the intake valves more, which, all else being equal, tends to hurt flow. This isn't as noticeable on a 396 4.094" bore (or .030) as it is on the larger 427/454 4.250" bore. There are some tactics to get around this, and, to a certain extent, it's not as much of a factor at low & even mid-lifts....and as noted it is easier to make compression with them, especially on a 396/402, which have limited choices for reasonably priced pistons. You can also "crutch" the flow issues with the cam. I still prefer open chamber heads though...
I agree with everything said here especially the part about getting a RPM Performer Air Gap, I would say this would be the best manifold for what you are doing, I have also had good luck with just a Performer RPM(not air gap) and even just a Performer dual plane, Weind Stealth is another good dual plane as well for oval ports. Two things i would like to add are I would remove your inner valve springs to run in ANY big block camshaft and if your heads have the rotaters you can buy a set of solid ones to replace the factory ones from any cam manufacturer that will fit straight in. I think they are .500 thick.
Ive gone a hell of a lot quicker with rectangle port heads in a street car as well usually because I have a bigger cam and convertor to match.
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