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street 455 build up advice
I recently added a 69 numbers matching GTO to my stash. I want this to be my driver (when I have time to drive one). I'm going to pull the original motor out and store it and build a healthy 455 to replace it with. Here are the parts I have to start with: 2-455 blocks, new Eagle crank as well as 2 factory cranks. 197 slightly opened heads with the matching intake. The GTO is an automatic with a/c, p.s and p.b's with a 3.55 rear. I want it to still be pleasant to drive but able to haul a$$. I might add something like a TCI street fighter converter but I wouldn't want to get loose enough to be real noticable. I definately need some cam advice (and rocker arm type and ratio) Built as a stout 455 HO maybe the stock rods are fine with good rod bolts?? I don't know. I'd like to raise the hood and have something that looks pretty much like a stock 455HO with the aftermarket Ram Air manifolds and runs really well.
Thanks for any help. Jimmy Daniel [email protected] |
Jimmy, you might review the thread I started a while ago:
http://216.178.81.108/forums/showthread.php?t=489745 I was fortunate enough to have advice shared by members of this board who have a lifetime of experience with these engines. My car is a numbers matching frame off restoration with what I term "invisible upgrades" to enhance it's performance and drivability. I have tried at each step of the project to throw the very best at this car. The engine is going to be 472 C.I. sporting an Eagle crank, Scat rod, Diamond forged and dished pistons (9.5:1 CR), new valves, springs, Harland Sharp 1.50 ratio full roller rockers, a Continental "tight" 10" converter, stock keepers and retainers, good valve job and very minor cleanup on the heads, intake and heads gasket matched, stock distributor curved and converted to "stock look" HEI, R.A.R.E. HO reproduction exhaust manifolds, Stock intake, Q-Jet, TH-400, 3.07, A/C, Power brakes, and Power steering. After a lot of consideration, I chose a Summit 2801-K as the cam. This cam is a really mild cam compared to what a lot of other guys are running, or suggested. However, as Jim Hand pointed out, this cam is bigger than anything Pontiac used from the factory. I don't like a really lumpy cam, just a noticable idle. The old cam was about the same specs using an UltraDyne cam on a tighter LSA of I think 108 or 110 which resulted in surging at a stop light. The wider 112 LSA of the Summit 2801 should result in an engine that produces MORE power and a smoother idle. I know it's counter-intuitive to put a smaller cam in and go faster, but I think with 9.5 CR to protect against a bad load of fuel, and unported heads, you have to be realistic about the cam choice. Putting in a bigger cam, on this engine will probably sacrifice torque in the range I'll be using it. My opinion is to build as much torque as possible, I'm not really concerned with the HP number game. Torque is what you feel. I can not take the credit for this cam, the 2801 was not even on my list until Jim Hand recommended it. |
While I didn't take the time to read 78 Ghost's link, if I can offer some advise...
Forget the TCI convertor, and get the 10" Continental unit everyone raves about...you will never be sorry if you get the Continental. Also, I have some completely reworked cast rods...the whole enchilada was done, and I always wish I had better ones in there. You see, as these darn engines evolve, and new parts come on the market, I realize I have to try to cram more power only by staying well below 6000rpm, unless I want to walk home. For the $200+ dollars to rebuild your rods, side-polish, shot-peen, magnaflux (first, of course), and ARP bolts, just get some new rods from a reputable source that checks the dimensions before shipping. Also, there are just too many cams out there. Jim Hand swears by his, and I really don't think anyone can fault him. The ram air manifolds will cost you potential power over headers, but I think you'll be fine. With that in mind, keep the cam moderate, add some exhaust duration, and be on your way. |
"The wider 112 LSA of the Summit 2801 should result in an engine that produces MORE power and a smoother idle."
More power is not the term. It's more torque. The 112 gives the smoother idle and vacuum. The 2801 less duration helps build torque. The cam I run makes more torque and HP than the 2801 would... But I have heads and the rest of the combo to use it. I think you have come up with a really good combo 78 Ghost. Should make 290 RWHP and be good for low to mid 13's. And make tons of torque. Plus all you need to do is port the heads and add 1.65 rockers to pick up another 40 to 60 RWHP as an upgrade with a cam swap and it will still be very streetable. Unless you did those things now so you have the 350 to 400 RWHP instead of wanting it next year... It happens to us all... |
I think the 2801 is too small of a cam for a 455. Sure it'll give you tremendous torque- probably more than you can use! I run a 2802 in my Lemans in what is essentially a stock 455- stock intake, Q-jet, stock unported heads, log manifolds. In a 4100 lb car (race weight) it has run 13.1's @ over 103 mph all while running through 3.08 gears. Still plenty of torque!:cool:
The car has great street manners and plenty of vacuum. I drive it anywhere with no issues. For a complete run down on the car click the link- http://www.highperformancepontiac.co..._4/benson.html |
here's my .02 i had a 72 lemans with a/c, p/s, pdb, stock spare and jack. with the gas needle on E it weighed 3850lbs. 455 stock crank, reconditioned stock rods w/ arp bolts, trw forged pistons +.040, plasma moly rings, balanced. 7K3 heads, bronze guides and new valves, no port or bowl work. stock intake with q-jet (only thing not touched) ram air IV cam advanced 2 degrees, rhodes lifters (audiable tick at idle but not like a solid), comp cams 1.52 roller tip rockers. stock torque converter and 3.55 posi. log manifolds, stock exhaust. idled like a puppy at 750rpm in gear, very nice to drive on the street with great throttle response and never lacking vaccum for the brakes. drove to the track (about an 1 hour 45 minutes away every sat and sun) ran 13.80's at 98mph. next year put on 1 5/8" headers with torque tech 3" exhaust with dyno max mufflers (no cross over) and a 2500 converter. putting on 28x9 slicks at the track, ran 12.70's at 105. still drove great on the street. put on 35,000 miles in 2 years with countless strip passes and was running strong when i sold it.
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I looked up the cam, and I realize it's the same one both I and a friend used about 20 years ago.
It was a bit small, but fine, in my 9:1 400 w/ 3.08 gears. My buddy had it in his 9:1 455 (bowl work), 3:55 gears, stock manifolds, and it was just too small. I remember it seemed 'done' by 4500 rpm, tops. |
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Bottom end,nothing fancy,choose your block,and use one of the stock cranks as long as it checks out OK,use some good aftermerket forged rods,even the budget I beam forged units are better than reworked cast rods IMO,also spring for some strong and light forged pistons (SRP,ross,BRC,et al),and use some good "file fit" rings,use one of the factory oil pans with the baffle in 'em,and use a good factory short windage tray,add a few oil drainback holes,and remove the scraper portion,use the bolt on style dipstick extension then as well,blueprint a 60 psi pump,maybe add a shim to get pressure around 70 psi,weld (or securely fasten) the pick-up to the pump also. Zero deck this block assembly! This is strongly advised here as this will help a bunch with getting the compression up with the 197 heads!!! Heads,well,this is gonna freak some resto folks out,but I would mill them to get the chamber CC's as close to 100 or so CC's as possible,just at or under a 100 would be fine,but no more than 100 if possible IMO,mill the intake side as needed for intake manifold fit too. And major gains are to be had with porting,so consider that as an area to exploit,either now,or in the future at some point. And again,not a lot of fancy hardware in the heads either,use a quality stainless +.100" length valve so you can set-up the springs to use the 1.70" installed height springs (crower #68405-16 springs),And get the valves with the undercut stems and flat faces,use a good quality retainer and the machined locks,and machine the guides to use the viton valve stem seals,and while you have them off,make sure they have all the exhaust bolt holes if you do eventually decide to run headers,and slot them for 1.65 rockers too. Use the cometic headgaskets,the 4.20"/.040" one should work nice here. Cam,,,well,,,this one screams hydraulic roller to me,,,I'd source a custom comp XE hr,use lobes #3315/#3316 for 282/288 adv.dur.,230/236 dur. @ .050",.510"/.520" lift w/1.5's,and have it ground on a 112 LSA,install it at 106 ICL. If you want my "conservative" hr cam choice,just use the comp xe276hr "shelf" grind,just a bit less HP,and bit more TRQ,still a good cam choice IMO. Use a good set of chromoly pushrods (custom length due to hr and +.100" valves anyways),and a quality set of roller rockers in a 1.5 ratio,or if the heads get ported at or over the 250 CFM range,then 1.65's would add some too. Quote:
Any number of good options for hiding a points to electronic conversion into a points distributor and making it virtually invisible,or the ultimate in "stealth" H-O hardware,convert a unitized distributor to accept the stock cap and wires and run that. As for the ram air exhaust manifolds,those were stock on H-O's,so they'll look right at home in there! Also be sure to use a good mandrel bent exhaust system,2.5" minimum,with good flowing mufflers and a crossover (X or H your preference). Use some painted valve-covers and a dual snorkle air cleaner and it will look like it was a "pull-out" back in '71!!! But with just a bit of porting (240-250 CFM) and said HR cam,500+ hp is very likely! Couple this with a good 2400-2800 "tightish" convertor and your current 3.55 rear,,,well,,,look out rear tires... :burnout: Should be more than pleasant enough for "daily" use IMHO. |
Thanks for all the input. I knew there were plenty of you guys out there that had already addressed this issue. I'll probably end up pretty close to Gray Ghost with my set up unless I do send the heads out for a little work. My 197's are coming off my racecar and I know they've been milled a good bit. I'm going to send them out first thing and have them cc'd to see where I'm starting from. Since I have an aluminum H-O intake, I will use it. Probably going with the 2801 cam. I have a new HC-02 cam, lifters that I didn't use years back but I'm guessing thats too big??
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Why would the HC-02 cam be too big on a 455? They just scream with that size engine.
I have a cam similar to what screamingchief recommends, but with e-heads and 11:1. Mine is an Ultradyne, with more lift, and it is very mild on the low rpm range, and is an animal when I get on the gas. |
So you think the HC-02 would be a better choice than the 2801 or at least as good?
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I would say with 3.55 gears, the 2801 will run out of juice, especially with those heads, and you could do much better.
I also think you could probably do better than the HC-02, as it is an old grind. Perhaps one of the newer, faster ramps would be better. You did say you wanted it 'healthy'. My 400 w/ the 2801 ran fine, but it was on the smallish side, and that was with stock D ports and 3.08 gears. My .02. |
After reading Jim's book it looks like a 455 H-O headed motor with the 041 and Rhoades lifters would be pretty strong.
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Biltit is running a 288/296 Hyd Ultradyne cam. It is a version of the 041. It rocks. He has posted sound and speed clips etc. Can't go wrong if you want good streetable power.
www.bulletcams.com Fill out the recommendation form and see which Ultradyne or Bullet cam they suggest. Can't go wrong there. |
I never see anybody talking about using 197's on here. I just reread Jims book last night and in the back with ALL those engine recommendations, they either used E-heads or D-ports. I still haven't gotten the heads cc'd yet (they are still on my S/ST car) but I know they have been shaved a bunch. I guess my question is, if I can get the compression in the 9 to 9.5 range, do these heads work well enough to use? I hadn't really planned on port work for a street car but if it's not going to work well without it, I may have to rethink it. I just like the round port and H-O intake look with dual snorkle air cleaner. A real street sleeper.
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Why wouldn't they work? They are very good heads, and it wasn't too long ago that most Pontiac people would love to run them over almost anything out there (over any D port). That was, of course, before the aftermarket came out with good solutions.
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When you say S/ST what do you mean? Are they on a race engine? If so do you know what the displacement is? You could do a compression test and see what it yields. That would give an indication of what to expect with the next build.
They should work for you. The TCI converter will be looser than a tight 10" continental. There is alot of cams and opinions. Ultimately think your goals through. We have all found ourselves buying more of the same parts as we desire the bigger push. If you start out really strong you may not want to go much further. I am unsure of how many people weren't happy with a ton of power. Most want more no matter how much they have. Truman Fields runs low 11's with an 068 patterned cam. It's all in the combo and want you want. It can't hurt to fill out the cam recommendation form on bullet's site. Call Comp, Lunati , Nunzi, KRE, Butler, PDude, Cliff Ruggles, whoever and see what they say. Jim Hand has built a power house street machine that speaks for itself and has sent many of us in the direction we are by his testing and imput. Good luck and have fun. |
http://216.178.81.108/forums/showthread.php?t=478701
http://216.178.81.108/forums/showthread.php?t=493124 www.putfile.com/biltit The 288/296 UD Hyd. cam w/1.65's RIPS!!! I would suggest it to any running mild-strong 455 on the street/strip. |
By S/ST I meant my 10.90 racecar. It's a 455 + .060. The heads are milled but I don't remember how much. It uses a Ross dome which if I was doing over again, I would do something different. I designed this engine in 1989 (when aftermarket stuff wasn't available) and ran it in supergas from 1991 to 1996. I now run a 598 BBC in my S/G car. I hope to soon switch to a Butler aluminum Pontiac motor.
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BilTit, how does your cam compare to the 041 w/1.65s? I'll be leaving for Atlanta (NHRA div 2 race) today so I'll be away till Monday but thanks to all of you for your help. I've been away from the Pontiac stuff for a whilw but I'm getting back in there.
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