Hey guys... I've been looking at my collection of engine parts lately and building stuff in my head. I don't have the scratch to do any of it for real, but it never hurts to plan ahead, right? Anyway, I know a bunch about SBC's... most/all of the common combos, as well as the pros/cons of each, max bore, max stroke, what needs to be clearanced where to fit this crank in that block, etc... When it comes to BBC's... Not so much! I have a couple of complete mid 70's 454's, a few later model 7.4 blocks & cranks, and a complete late 70's 427T. So, after all of that, here are my questions! Any ideas as to practical max bore/stroke that these blocks will take? What would you guys build using these blocks? Would I be further ahead to throw a 454 crank in the 427T and build a super long rod 454, or throw a moderate stoker crank in it with pretty long rods, or throw a huge stroker crank in it and go BIG, or ??? In a properly balanced engine, what are realistic RPM limits using factory blocks? Rods? Cranks? (In other words: I know these can make a ton of torque, so how high could you realistically raise the power curve to help get out of the hole?) Same question as above, only for HP limits? Are there any special, BBC specific things I should be aware of for hot-rodding them? Any advice/experience you'd like to share? Keep in mind, anything I build will likely be for a normally aspirated, streetable (by MY terms) race car (10's or better!). Any info you guys can share would be greatly appreciated!!!! Thanks a bunch! Steve
Here is a fairly cheap combo...use either block...max bore .060...Elgin + 1/4" stroke crank and 6.385 rod. Cam...Comp 292 or 305 hydro duration with 555 lift (get good valve springs). #781 oval port heads...just port match them to your intake and leave a step in the exhaust. 2" tube headers, cheapo windage tray and HV oil pump. Just a tick under 500 ci with this combo...a real torque monster so pull a low gear (355..maybe 308), 850 crm on a good intake and you can make 550 + hp and a ton of torque. With the BBC you have to fight cooling problems...I recommend HV water pump with billet pullys that will twist it 30% over. Run a standard stat...and that will be enough restriction to make it cool OK. You may still need a big fan or Spal ele fan if you live in high humidity part of the country. Anyway this combo has worked for me in three vehicles. With a good balance and clearance job I twisted my 7500 without lifting my feet off the floor (456 gear). It really like it up to about 6800 (355 gear). 2700 lbs car. Good luck...and the best place to start is on paper...just don't wait too long to start building, the price of BBC parts just keep going up and up....like they are gold. Ron.
Steve, When you go to big blocks throw everything you know about small blocks out the door. They are a completely different animal (with emphesis on the animal part). Trying to make an RPM motor out of them in hopes to get out of the hole is a waste. For anything on the street (and most drag applications) RPM on the starting line is NOT your friend. Except for 16" tires at 5 lbs. of air and a pro stock ch***is you'll find yourself picking an RPM much lower than the peak torque, drive it out while feeding in the throttle until it will take full throttle and hope it won't go up in smoke until your wide open. After that the cam profile and breathing will dictate the shift points. HANG ON!!! Frank
ONe more thing. A small block has , for the most part, been tolerant of low oil in the pan and still surviving. I had a friend who never checked the oil and only added when the pressure dropped a high RPM. DON'T try that with a big block or you'll be driving over the crankshaft. They just won't tolerate a loss of oil pressure at the bearings when making horsepower, not even for just a second. Frank
For a good compromise in a streetable race engine, I would use the earlier (Mk. IV) tall-deck 427 block with a 4.25"-stroke crank and .250"-longer rods. A .030"-overbore gives you a 489, and 060"-over makes a 496. The later Mk. V and Mk. VI engines are okay, but you'll find far more performance cranks available for the earlier big blocks. There's a page with casting number and other information at http://www.roadsters/.com/bbc/ Another page describes my 496 and 454 projects, at http://www.roadsters/.com/power/ Dave Mann (602) 233-8400 weekdays http://www.roadsters.com/
I like to keep up on my BBC stuff over here, Harold Brookshire/Ultradyne/Lunati cams is there, etc. Lot to read, lots of combinations to consider..... http://www.chevelles.com/forums/forumdisplay.php?f=13 The new Lunati VooDoo cams are Harold's creations with new technology ramps, I'm getting ready to install one in a 454.
I ran a .100 over 454 for years. Stock stroke, "dimple" rods, TRW pistons, Merlin sq ports. With a .680, .714 roller cam I shifted at 6800 and trapped at 7800...hundreds of times! The crank was a Chevy "non twisted" forging. Compression was 14:1. The previous combo was a 468 2 bolt block (+.060), 11.25:1 compression, and a .672 Cam Dynamics roller. What was nice about that one was lots of vacuum and easy on springs. Also had a cast iron drive gear for the distributor. Keep the springs oiled by using the restrictors at the back of the block, o-rings removed, then o-ring the distributor. Makes em live. Don't go big on the rod and main bearings. It's an old wives tale! Keep em in the middle of spec. Heads are whatever you can afford. Spend the time to get the valvetrain geometry right and light. A top quality 3/8 moly pushrod lasts longer and is way lighter than the popular 7/16 choice...oil in the pushrod=more weight! Good luck with it. There's nothing like a fire-breathin BBC.
Basically... aftermarket blocks are out, billet cranks/rods are out, ***anium internals are out, etc... I'm not afraid to buy decent (read: readily available) aftermarket cranks, rods, heads, stuff like that; but the Arias head conversion might put us a little over our "play" budget!
You'll probably want to build a 496 with a 454 block, steel aftermarket crank, and aftermarket heads. There are a lot of possibilities.
Exactly! I would do a 4.250" stroke with aftermarket heads. Don't get overzealous and put too big of a head on it. (ie Brodix BB2+) A guy who used to work here has done a bunch of different BBC stuff over the years culminating with the 1200hp 598 in the orange Chevelle that was at our openhouse last year. He had a 427 in a Regal that went 9s with a stock crank and rods. Making power with the BBC is easy. I can get you a good deal on Eagle and **** stuff...
Keeping in mind the words budget.... If you have a good steel crank I would not think twice about putting it in your tall deck. Then you can run a .400 long rod with an off the shelf (forged) piston. Punch that block out 0.060 over and have a nice 468" deal. With the money you saved on a block and crank you could spend it on better valve train parts. I went drag boat racing on a Top Raman budget. I ran a tall deck truck block (no money for bow tie stuff) with a 0.010 / 0.010 steel crank. I did have a set of Carrillo's but they were at least 10 years old when I bought them. With a set of JE pistons and 30 pounds of blower boost I'd spin it to 8,800 on the big end every p***. It was hard on valve springs. lol I still have that engine waiting for a G***er project someday.
Primer you lookin for some big block stuff I've got a steel crank a set of rods a block 2 intakes and a set of square port aluminum heads I think their L-88 heads and some other bb stuff. Pat
I personally like the tall deck blocks if you have room for their 400 thou higher deck height. They have beefier bottom ends with all 5 main caps 4 bolt, and the caps are bigger to boot. The cylinder walls tend to be thicker also. If you are going to run a stroker on pump gas with stock heads, go with an open chamber head like the 049's oval ports. They have a huge 122cc chamber and flow really well. The large chambers let you run a small dome piston instead of a dish. A really good running combo I have done is a 427T block 60 over, 427 crank with a set of closed chamber 215 casting heads. I used a long set of **** rods and a piston for a 496 from Ross. I think it was a 6.8" rod but I will have to look it up. I had the ****er balanced and a 262/270@50 Crower Roller cam in it and a Wiend Team G intake for oval port tall teck and 4150 series carb. A tweaked 750 holley (flowing about 1000cfm) fed it. 2" headers and short 3" exhaust. Compression was about 11:1. Ran fine on pump gas and was twisted to about 7000rpm. With the light pistons and long rods, it thought it was a small block when reving and made enough steam to get a 3400lb 2nd gen F-body into the 10's on motor alone. I sold the car 2 years ago and the engine is still running, but now has a 200shot on it and runs inthe 9's.
On the note of THAT kind of stuff, I have a guy trying to sell me a 427 out of a '69 (I think?) vette. It's a tripower engine, but the intake/carbs are gone. It's standard bore, standard crank, etc. It's all there (other than intake/carbs), but dis***embled. I think he's asking too much for it just for a hot rod motor, but for a vette guy that cares about the numbers, it's probably not a bad deal... What would you guys consider a fair price???
If all the numbers are still on the deck and its a 435hp version....5g's easy to a vette guy. It will he a 4 bolt, rectangular port engine for the 435 hp, 400hp was a oval port engine...still worth a bundle. Last time I priced them was about 5 years ago...I bet they would go for double that today.
I have a couple of complete mid 70's 454's, a few later model 7.4 blocks & cranks, and a complete late 70's 427T. Any ideas as to practical max bore/stroke that these blocks will take? What would you guys build using these blocks? Would I be further ahead to throw a 454 crank in the 427T and build a super long rod 454, or throw a moderate stoker crank in it with pretty long rods, or throw a huge stroker crank in it and go BIG, or ??? In a properly balanced engine, what are realistic RPM limits using factory blocks? Rods? Cranks? (In other words: I know these can make a ton of torque, so how high could you realistically raise the power curve to help get out of the hole?) Same question as above, only for HP limits? Are there any special, BBC specific things I should be aware of for hot-rodding them? Any advice/experience you'd like to share? Keep in mind, anything I build will likely be for a normally aspirated, streetable (by MY terms) race car (10's or better!). Steve, I am in the build stage of a Gen VI 454. I am using a Eagle 4.25" 4340 Crank, "H" Beam Rods w/L19 Bolt upgrade, Edelbrock Heads and Intake. The reason that I am using a Gen VI? Factory Roller Cam, 4 Bolt Mains, more clearance for Stroker Crank (some guys say you don't have to clearance Block for 4.25" Stroke). The downside of the Gen VI I hear is that you can't go more than .060 overbore. The reason that I didn't go bigger (540) is the limitations of the Edelbrock RPM Oval port heads-I wanted good street manners which generally dictates an Oval port head (good turbulance), but the Edelbrock's have what they call a Roval (Rectangular/Oval) port design. The Rectangular Port heads are great for high RPM, but generally suffer at lower (read Street) RPM's, so it is kind of a trade-off. There are better Heads (read:more expensive) out there-the 781's recommended above are probably a good choice. The "Dot" Rodscan be used up to 7000 RPM with 7/16" Bolts, 2 Bolt Blocks to 700 h.p.. Sounds like you may be a Square port guy-be careful-Big Blocks have a heavy Valvetrain, requiring better quality components for high RPM usage-all of the above is IMHO-
The key to big blocks is money. If you don't have a big budget you will not be building a high rpm big block, period. You really don't want high rpms to get out of the hole on a street/strip car. You want high torque at low rpms. In my opnion you are dreaming if you think you can make a 10 second big block street car on a budget, unless you have a really light car you are gonna have at least $5000. in a big block capable of running in the 10's in a heavy street car. That being said I believe it is possible to make a pretty fast (mid to high 11's) street/strip car for much less than it will cost you to make a 10 second car. Example. I have a 3400 pound Chevelle. It runs low 11's. I have a 1970's 454 2 bolt block stock bore, stock cast crank, stock rods with apr rod bolts, cheapo hypereutectic pistons 10:1 compression, lunatti hydralic cam 232/239 .549/.558, Edelbrock performer RPM intake, Holley 850 double pumper, GM cast peanut port oval port heads with mild porting done by me, stock valves, high volume oil pump, true roller timing chain, hei ignition with MSD 6al ignition box, big headers, turbo 350 trans, Dana 60 rear with 4:10 gear and 29" tires. The car runs low 11's and I can rev it up to about 5600 RPM. If I were to replace the hydralic cam with a solid cam I know I could rev it up past 6000 & run in the 10's but for how long? To build the motor the way I have it built now cost me about $3000. In order to run the same motor at high rpms and make it last I would need at least a forged crank, good rods & a solid or roller cam those 3 things right there will run you $2000 or more. But really I would also need better heads, big valves, good springs, bigger better pistons, etc. It all adds up really quick and before you know it you will have thousands into it. My advice is to build one of your 454 short blocks b***ically stock. Add a decent cam, find some 781 or 049 GM cast iron heads, get a Edelbrock RPM performer intake and a good Holley carb, stock HEI dist with MSD ignition parts and be done with it. You will end up with a streetable big block that will run in the 12's without trying and you should be able to tune it into the 11's pretty easily and you won't have to worry about breaking parts because your trying to run it at 8000 rpm. Just my opnion. Also the other advice I have for you (I learned this the hard way) is to stay away from any and all used big block performance parts. The worst thing you can buy at a swap meet is someone elses used up big block parts. Good luck with the project..There is nothing better than a big block Chevy. Warning, once you go big block you will never go back.
The thing is, I have a 3100 lb street car that runs high 10's@125 (and can knock down 12-13mpg if I keep my foot out of it!), with a SMALL BLOCK! If I built a bigger motor and the car went SLOWER, that just seems silly! Like I initially said, I can build a pretty strong small block; now I want to try my hand at making some BIG power! I know what you're saying about a budget; I know that it takes money to go fast... I'm just trying to figure out what money can be saved by using factory parts...
What ever it cost you to build the 10 second small block multiply by at least 2 to get the same out of a big block. Yes you can get BIG power out of a big block but I don't think you can do it with factory parts. You can use the 454 block and a "factory" forged crank & GM's best "factory" heads but why? The only factory GM part I would use if I were going big & high RPM's is the block, and I would want that zero decked, filled, machined, etc.. The factory forged crank will cost you more than an Eagle or **** or even Ohio Crank. By the time you rework the factory heads you will have more money into them than a pair of Merlins or Brodix out of the box heads. I would love to build a BIG high horse big block myself, and I have tried to figure a way to do it on the cheap, but I just don't think BIG big block & cheap go together. I have another big block that I have been building now for almost 2 years. It will be a 496 shooting for about 700 HP. I got the stock block for $400. Chevy 454. I had the block bored 60 over, zero decked, blueprinted, etc. good machine work cost me about $800. I have good forged pistons at about $750. Eagle H beam rods at about $500. Used Merlin cast iron square port heads $800. Edelbrock Victor Jr. about $250. So far I have about $3500 into it. I still need a forged stroker crank, gasket set, bearings, deep oil pan & pump, cam, lifters, valve springs, stud girdle, tall valve covers, timing chain, rotating ***embly balanced, harmanic balancer, flexplate, plus all the other little **** that always pops up like good bolts. I figure I will have at least $5000-$6000 into it not including carb, water pump, fuel pump, good radiator, etc..Can you build a BIG high horse high revving big block Chevy? Yes you can if you have deep pockets. Which unfortunatly I don't.
You can run 9s on a cast crank and stock rods... but for how long. I think a stock forged crank would be fine... but you lose the cubes. Factory rods with good bolts should survive as long as you don't rev the piss out of it. Where you are going to make the good power is with the cam/head/intake package (as with any engine) I have a guy who has what he calls 'module race engines.' He has junk short blocks with cast pistons and cheap rods but killer heads and intake. Whenever he hurts a motor, he yanks the good stuff and plops it on the next shortblock. Not the best scenario... but he is running 9.50s (although SBC and lots of nitrous... but you get the idea)
That's what a lot of the street racers around here do... Junkyard shortblock with a great top end/valve train, spray the hell out of it til you win... if it grenades, swap it out for next weekend! They have cars that might dip into the 12's on the motor, and they're running low 10's or better on spray!!!
You could always buy my 427... http://www.jalopyjournal.com/forum/showthread.php?t=106633 This motor was built for a Chevy High Performance magazine article last year. Buy it before I find an old beater to stick it in!
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