Alright, so here's the debate. I've got a 355 smallblock that's got 2,000 miles on it from a really good family friend. It's complete and has some nice forged flat tops sitting at a 10.5:1 compression with the also fresh 882 heads (yes, STOCKER heads). In the process of buying the engine I've gone out of my way to try to make things better, and I want more power.. but the more I think about it, the more I wonder if I went about things the wrong way and spent money where I shouldn't have. I know there's a ton of people here that have HP expectations, and while I'd LIKE to have "xxx horsepower" I don't really have expectations aside from it being fast at the strip. I want a 11 second car and I'd really love to hit high 10's, but I seriously doubt that's going to happen with my current setup.

Current modifications:
Hedman longtubes
TH350C with a Hughes 2500 stall and manual valve body & B&M racing trasmission cooler and Megashifter
Comp XE274H Hydraulic Flat tappet
Performer RPM Airgap Intake
Quickfuel 750 Annular carburetor
Edelbrock 1721 120GPH fuel pump
Reworked 882 heads, but I also have Dart 200CC Iron Eagles lightly Ported and Polished with 7/16 1.6 Harland Sharp rockers
Misc ARP hardware, Felpro gaskets, and chrome dress parts, subframe connectors
STOCK rear with 3.42's. This will pose a problem with the 454 (and even my current motor), and I'm fully aware I'll need to address this issue.

No idea what kind of power I'll be putting out with my current setup. Probably not a whole lot because my cam isn't very radical and I built it to be fun on the street with some strip elements in there. With that being said, I've got some money put into the setup (about $5,000 overall), but nothing overboard. I also built this motor with the best I could afford with intentions of moving forward later if I needed to.

Here's the question: should I run the SBC for awhile, save my pennies, then sell the motor and buy one of Phil's machined 454 blocks? Phil sold me the 355, but he's got a 454 block fresh .100 over ready to assemble for $400, I just need the other parts and I think he's got most of those that he'd sell to me for cheap. I just figured maybe a mild BBC would get me to my goals better than the 355 would (or a stroker for that matter). I want power, and I feel like buying a 383/396 stroker kit with me saving up might be a waste of money when I could buy an equal setup for the 454 for a little more.

Opinions? Anyone who has a BBC swap feel free to chime in on what it cost you to put a mild one in. I just want a foundation I can build on for many years to come and have fun with. I was thinking along the lines of a MOSTLY stock 454 build for now with a mild cam (like the one I've got to match my stall), as well as an intake and using the carb I've got now. Apparently the stock heads are pretty good for the kind of power I want, and I can save up for some really nice ones later (or port the stockers if it's worth it?).

Anyways, I know I've typed alot. I just want help figuring out a gameplan. I'm not partial towards either motor, but I've never had a big block and I want to know more about what it takes to build one for one of these cars.

 

I dont have a BB swap, but i have a BB for sale that is N/A and 520CI making 670+ HP and 625 FPT @ ~ 5800 RPM...the SB is a tat lighter tho..other then that ..there is no tourge monster in a SB..in a BB ( short deck ) u can go 540 even 572 CI and hav huge tourge.
If its also a daily driver i would go Sb..but if u use it for fun and strip and maybe around the city..i would go BB ( MILAGE SUCKS ) LOL
But hey , thats only my opinion.

BTW, with a 454 ( stock ) use the 355 ( faster ) !!!!

 

They have big blocks that they run factory casting heads on, you have a few options...
Some stroke their motors to 496 cubic inch monsters, run a streetable cam and produce an easy 550 horses...
Others keep the 454, run a streetable cam and see about 1hp/cube.
And then I've seen very large non streetable cams in 454's that can put down 10's.

All these set ups they run head casting 781, usually around 9.5:1+ compression, and the heads are machined to accept larger valves. They are the best flowing big block heads for the buck after machining. A lot of these guys run stock rods and crank (unless stroked obviously). I was thinking about taking my old 454 .060" over, running machined 781 heads and reringing to plasmas with a 100 shot. Figured it could turn a low 11 second quarter relatively easily but I sold the motor.

 

Sell the 350 and do the 454. 781 heads respond well to porting doesnt take a whole lot to make them breathe and dont need much cam to make them haul butt. Youll be a torque addict for sure!!!

10.5:1 350 with stock iron heads is pretty dicey on detonation not much you can do with those heads honestly. A used 350 just wont bring much fwiw.

Your brakcets pulleys and headers on the BB will cost some just watch ebay for deals. Youll never go back to a SBC again promise. A mild cam with some bowl work on the BB will have you smiling all the time.

 

How much do 781's normally cost for a pair ready to bolt in? I'm still trying to figure out how much a mild build costs to put together. What did it run you?

 

If u realy go 454..u will not get 550 HP ...NO WAY !!!!!!

BUY THIS , all u need..before the rear end says good bye..lol

 

If you put those Dart heads on your 350, you'd have almost exactly the 350 that I pulled out of my car to replace with the current BBC. That small block made probably 400hp crank, maybe a little more. I dunno what it cost me to build, but the BBC that replaced it was a 454 with stock small valve 781 heads, tame hydraulic cam, Hooker swap headers, 870cfm Holley, RPM intake, and the MSD ignition that I had on the 350. I'd bet the BBC makes just as much HP, more torque, and is ALOT more user friendly than the 350 was. I don't regret the swap for a second. The cost between the two motors was probably close... the small block required more upgrades to make that power, but even though the 454 required fewer upgrades, they cost more. It was probably close to even for cost, aside from the stuff I just swapped over from the 350 to the 454.

You could probably get a set of serviceable 781s for $500 or less, depending on where you are. My 454 came with them tho.

Its painfully easy to get 550 crank HP from a 454. What they really need to really bring them to life is a compression boost and a decent cam. Once you have those, 550hp is easily achieveable with any of the large oval or rectangle port heads. Even the small oval 'peanut port' heads are known to make 400+hp unported, and they have about 60cc smaller intake ports than the 781 'large ovals' which are around 260cc. Factory rectangle ports are around 290-300cc. Use the 2.19/1.88 valves in any of the large oval or rectangle port heads and they will support 550 crank HP all day long.

Go big block.

 

I'm seriously considering it. I just wish I had all that money back to be able to think over everything all over again but such is life. I think what I'm going to do is drive it for the time being and try to find a buyer for the motor, and then I'll just yank it when I'm ready and build a mild 454. Also - this car is NOT a daily driver. I have a van for DD'ing.

Also - can I run a more radical cam profile with a BBC and maintain good vacuum because of the increased engine dimensions/output or is it the same physics that apply to a smallblock as far as LSA?

 

I dont want to start a pissing match..but i still say NO ...i build marine race engines..and a 454 ...NO,,maybe at 7000+ RPM with a dragster cam..lol

Anyhow..i 'm out !!! NITE

 

The same basic idea applies, but the big displacement increase will 'absorb' alot of the aggressiveness of the cam. What I mean is, a cam thats pretty wild in a 350, would be tamed down ALOT when using the exact same profile in a 454. A cam that would be gigantic in a 350 would likely be pretty mild in a 454.

 

454ci (468ci with an overbore), 10:1 - 11:1 compression, 781 castings with 2.19/1.88 valves, RPM intake manifold, 870 Holley, long tube headers, hyd roller cam in the 246-250* @ .050 range.... shouldn't have a hard time making 550+ crank HP.

 

OH...well, now your talking major rebuild..yes flat top and bore..with a 10.5 comp i dont see a problem making 550 HP..but then it would be easyer to find a 502 and cam it , stick a nice intake on it with a 850 holley and use aluminum 245 heads ..DONE !!!!!! and still have enuff beef to go way bigger down the road !!!!!
I would even stick 2.30 / 1.90 valves in it !

 

Here's the block information about what Phil is selling (he's got these on CL but hasn't gotten a buyer.. he'd also sell these to me for cheaper if I chose to buy them from him)

Chevy 454 Big Block Engine: Casting #3999289, date code A-30-75. All machine work done professionally in St. Louis. Blue printed, line bored, bored .100 over, decked , and lifter holes bored to exact size. $475.00

Chevy 454 Big Block Engine: Casting #361959P, date code B-6-76. All machine work done professionally in St. Louis. Blue printed, bored .070, line bore Ok, block deck. $350.00

Chevy 454 Crank: all steel, oil holes machined and balanced 70/71 LS6, Casting #3967416; real nice and heavy duty $400.00 firmChevy 454 Rods: from LS6, special free floating with 7/16 studs, dimple on the rod in good shape. $250.00 firm.

I expect in the event I get the cashflow they'll still be there. I'm still wondering if it would be better if I just get a pullout instead and just build around that.

 

When did I say you didn't have to dig into the bottom end? My first post mentioned a compression boost... I just implied new pistons.

 

IIRC, the dimpled rods are the heavy duty rods, having more material thru-out the beams. May be mistaken on that tho.

My '75 Camaro had a bigblock--
Short deck
454 + .030
Stock crank
Stock dimpled rods ( 6.135? )
.250 Hyperutech domed pistons
Closed chamber '69 rectangular port heads stock valve sizes ( yup, small )
.544 lift Crane cam

It took some time to save for it all, close to $3000 total investment.

 

I don't want to start a pissing match either,but you haven't a clue if you don't think a 454 can put out 550 streetable HP.

 

The car in my avatar,was a street/strip car,not geared whatsoever towards handling.I ran just about any combination of SB in that car that you can imagine.I bought it as a hs student in 1992,and ended up selling it in 06.
Originally a TPI 350 car,once it was carbed I ran everything from a 283 to a 421 in the car,the last SB being a solid roller 406 with RHS heads and more cash than I care to admit invested.It would run low 10's with a 125 shot of NOS,but I broke 2 blocks in a 12 month timeframe,due to the inherent weakness of the stock 400 blocks.
After that,I pulled my wounded aluminum headed SB out,and put in an iron headed BB.
It was a 468 ci,10.4:1 compression,ported 781s with 2.19/1.90 valves,the a COMP XE 274 hydraulic cam,and performer RPM intake,and800 CFM carb.It ran within a tenth of the radical SB on the same shot of spray,and was ten times more drivable on the street.Dollar for dollar,the BB delivers way more streetable power than a SB,cubic inches=HP,plain and simple.

 

I think u do , a 468...IS NOT A 454 !!!!! just saying...hahaha

I probably spend more time in a dyno room then any of u in your camaro..SO PLEASE show me some DYNO results !!!!

a 454 ci engine will not put out 550 HP unless 13+ :1 compression ( on 110 octane ) and a bunch of head work with aluminum heads ..or blown ofcoarse !!! ITS A FACT !!!!! not my guess !!!!

 

That's actually right around the build I had in mind believe it or not. Hmm, interesting.

 

I tell ya what,why don't YOU show some dyno sheets.
A 468 IS a 454,.060 over.There's no magic or trickery to boring an engine,it's part of any typical rebuild.
Put up or shut up,I'm calling BS on you.

 

For someone who is an expert engine builder,I would think that you would be aware that "flat top and a bore" will NOT yield 10.5 comp. in a 454,even with the tightest of chamber.The 781 castings in question are typically in the 119cc combustion chamber,and usually the engine beneath them had flattop pistons stock.

 

HAHAHAHAHAHAHAHA

 

Hey hey, guys - cool it.... there's some good info in this thread, I don't wanna lock it. Don't make me. Back on topic please, or I'll just lock it and call it a day.

It IS very possibe to build a 454 (with overbore or not) with under 11:1 compression that will make 550 crank HP with stock or lightly ported 781 castings with big valves in them, and the right camshaft. And it will be quite streetable too, especially with a modern hydraulic roller grind. Guys have been doing it for years.

Marine race engines are not the same as automotive race engines - the engines are built differently because the running conditions are completely different, and the required powerband for that kind of use is also quite different.

 

When you say "right cam", do you mean something wild, or are we talking one of the more milder cams? How do BBC's respond to solid cams compared to SBC's?

 

They respond the same as any engine,solid lifters are lighter,therefore making a more responsive,slighty quicker revving engine.
I myself am pretty fond of staying in the .550-.570 lift range,with 250* or less of duration @ .50 lift.They are getting pretty choppy at idle in that range,but still streetable with a looser convertor.My intake of choice with that combo and oval port heads would be the Performer RPM,or a Weiand Stealth.There are those who swear by an at least 850 CFM carb.Again my opinion,but my favorite card is to combine the 750 CFM HP Holley main body or Pro-Forms equivalent,with a baseplate from an 800DP.This slightly smaller carb in my experiance is much more responsive and streetable,although it will give up a very little amount of HP in the higher RPMs.

 

I'm happy to say my Quickfuel will do it's job nicely if I jump the gap, particularly because it's an annular as well. Any idea where I can pull the accessories/brackets from (or the easiest place to find them)?

 

Because BBC uses larger cam profiles than the mouse, and the limits of flat tappets, it is in your best interest to limit lift below .600" or use roller lifters.
Even more than it's baby brother roller tappets should be considered as standard equipment for the performance Rat, largely due to bigger valves, stronger valvesprings as well as the much greater lift.

My "truck" engine is .530"x.560" lift on flat hyd, purrs like a kitten at idle...

550hp from a 454 is no problem for me, (you will want a roller cam) I'm sorry some find it so difficult

 

I hate to say it,but there are some really nice polished aluminum brackets on Ebay priced really reasonably.They are,however,chinese parts.I haven't looked into pulleys in a while,but I would assume that the same folks make those,as well.The last time I had to piece the bracket/pulley stuff togethor,even March stuff was cheaper than new GM stuff,and it's really difficult to find used factory stuff,that doesn't come with an engine attached to it.

 

I think what I'm probably going to do is attempt to find a complete one and build around it. I know someone who can help me find them for really good prices as I've bought other motors before through him. I've got options right now, but this might be the cheapest opportunity while still allowing me to throw money at it. I will say one thing though - it APPEARS stock casting heads are expensive as **** for these motors.

 

A lil info a friend gave me---

http://www.chevelles.com/forums/showthread.php?t=630

post #6 & #15.

 

Welcome to the world of the BBC.... everything is expensive compared to a SBC, but $500 stock BBC castings will support as much power as $1500 aftermarket SBC heads will, so its really not such a bad deal in reality. Its a pay-to-play deal. What castings were you looking at?

 

781's, and apparently another casting similar to it on Ebay. I respect the fact the lunch isn't free, though. If it were, everyone would be running BBC's.

 

The thing with the BBC, is that even though factory parts cost more than SBC parts, they usually cost alot LESS than aftermarket SBC parts... and BBC factory parts usually can support the same or more power than those aftermarket SBC parts - so you're still money ahead in the end.

 

I got a 92 camaro with a 1978 454 from a motor home. 8.5:1 Compression ratio. Put a mild roller cam in it (280 dur@50, 110 lsa, .500 lift) stainless roller rockers. Put accel DFI single plane intake on it with 36 pph injectors, and a 1200 cfm throttle body running sequential. Hooker super comp long tubes 3 inch collector, Dual 2.5 inch pipes with flowmaster 40s into a 3 inch merge collector to a side exit.

T5 trans, 11 pound flywheel, BMR K member/A arms/crossmeber/torque arm.

Stock 1 wheel peel 2.73 axle, 255 wide rikken tires.

Car Weighs 3280 lbs with me and a full tank of gas.

Best time was 13 flat with a 127 trap speed. I don't shift hard and I roll into the throttle. With a TH400 and a properly geared locking rear axle she could go alot faster.

Its also a junky motorhome engine that only had a cam and rockers put on it so a built engine would make alot more. The dyno sheet is for flywheel output on a water brake.

It cost me about 2500 to 3 grand to put mine in the camaro, but I spent a lot of money on unneccesary stuff like arp fasteners, march serpentine kits, aluminum flywheels, sfi balancer, oil cooler, etc.

I get 12mpg city and 22-25 on the highway.

I think the reason a big block is a better choice for a street rod is the much larger ammount of torqe and the much wider torque curve. More usable real world power. Its just very difficult to get mileage out of it too.

 

How much did you pay for the engine, and how many miles did it have on it?

 

I got the complete running engine all accessories and TH400 trans for 500 bucks. It had 38 thousand on it. Somebody's dads motorhome that never got used. You should be able to pick up a used running engine for less than a grand.

 

Update: I found a set of custom headers for the swap for low(er) dollar. Might sell my SBC Dart Iron Eagles for cash then buy the headers and save my pennies for a big block.

So tempting, but it feels so far away at the same time. Bah.

 

my vote says big block. If you have a th-350, you could run a crazy high gear like The Devastator, and still have plenty of torque so you can have some fun as well as low highway rpm.

If at all possible, get some aluminum heads... thats an 80-100lb savings in itself.

but then again, bbc stuff is more expensive. A mild HR cam, aluminum heads, and some other stuff equals a bbc equal in weight to a stock sbc AND much more HP without revving over 6000.

BBC all the way!

 

Woah...how are you getting 35 mpg in a BB Camaro, in Ca no less (how do you smog it) and trap 127 with a 2.73 gear?


Yeah, Ok. If Im not making that much its awful close and Im using a flat top 350. Large solid roller and heads to get there but so what. Also got close to 15k in it.Ugh

A 454 can do it easily

More importantly its a street car so how about 550 ft lbs on the 454 vs the 350? Now youre talkin. The BBC heads arent cheap but youll never go back to a small block unless you need the weight savings to handle. Headers could be a challenge and youll need a killer cooling system. Sometimes the mildest are the most fun.

Example-Used to run a 85 5.0 with a mild 460, low compression, 280 Nitrous cam with (100 shot)Rhoads lifters ported SCJ iron heads, extrude honed Offy intake. All painted nothing chrome except valve covers and air cleaner. Unles you knew Fords you couldnt tell what it was

Let me tell you something that car was an animal and you could walk most guys at part throttle it was a lot of fun. Very mild easy to drive and required almost 0 maintenance. Never dynoed it never cared it was stupid fast. In fact I even took the 4.10 gear out and put a 3.55 since it was so much fun to drive and still pulled the gear well. Converter was a bit tight but it lived.

That was back when smog laws got real strict so it got sold out of state.
THe Rhoads pieces worked well, once warmed up you could hear almost NO cam at all, it drew in a lot of flies.

You can do a whole lot with a 350 but to get 550hp takes a lot and youll spend at least as much building it reliably as you would a mild Big BLock.

 

How about this?


take your 350 and stroke it to a 396
AFR 210 head could squeak by with a 195
HR cam 236/242 or a solid roller in the 240ish range
A performer rpm would be fun on the street but a good single plane better.

Youd knock down 11s all day long keep the weight off the front end keep your brackets mounts more header options easily top 500hp/tq. AND fool a hell of a lot of people. Not that much to build one.

 

That's actually my other option, but getting a 396 kit will be ~$2,000 since I can't buy one without a forged crank. I already have a good solid from Lunati picked out, I just need to decide realistically which I want more. EITHER WAY - I'm getting a big block.. I just don't know if I want to wait to stuff it in a Monte Carlo or just put it in the Camaro instead. I like trying a little of everything so I'm definitely doing a swap, it's moreso what I want it in at this point and WHEN. When is the big question.

 

396 out of a 350 requires a 3.875 stroke crank. in a stock block that wouldn't be wise. if you are going to spend that much on a rotating assembly, you might as well get a dart shp block with a 4.125 bore. 400+ cubes.

check this out-> 553HP 327, 11:1 CR, pump gas.

OR get a factory forged crank for a 454 bbc, some 4032 forged pistons, eagle or scat rods; only about $1000 for a sturdy bbc bottom end. Spend your money on heads! That will be the determining factor to how much hp you will make, and how much room for growth you will have.

when i was debating sbc vs bbc, i went through the same thing. once i realized that a high hp sbc will be expensive and still not yield the same power as a bbc, the choice was clear. By no means are sbc's bad, but for max performance, bbc will be superior.

take that $2000 and spend it on some AFR 305cc magnum rectangular port bbc heads. you don't need to get the full cnc option, and the flow #'s are still high.

 

Nice numbers for a 327 but it doesnt even make 400 lbs of torque til 4600 no thanks.

OP if its a BB you crave then go for it. Theres a guy on chevelles.com named VORTECPRO who can get you what you want done for way less than you think.
Check him out. His specialty is driveable hi torque BBs without breaking the bank, good reputation. Go to the performance section and page him.

 

 

I have a good friend who said the same thing about the aftermarket race block if I plan on spending that kind of money (which makes sense). I have considered it because the cost is the same, and there's MANY ways I can throw $2,000. I just like to weight my options with everything before I take the plunge, especially since $2,000 doesn't come to me quickly. Better smart, than regretful.

 

Heres the guy I told you about....great reputation can build any BB you want but specializes in affordable low compression BBC....check out his site on the 'bay (enter VORTECPRO in search). Never heard a bad thing about him, heres one example

http://www.chevelles.com/forums/showthread.php?t=342085

Hope the mods dont mind just passing some info along of someone who will treat this guy right.

Now does that help $/power with your decision?
Confused? Cant sleep? Are we helping? lol

 

I'm getting 22-25 on the highway. Its mostly because of the sequential fuel injection, gearing, and the super tall overdrive on my wc t5 (.5). at 80mph it turns about 1300 rpm. I've also got stepped longtube headers run into a y pipe, run 42 degrees total timing, mix 91 octane 50/50 with 100 av gas, curb weight 3280 pounds with a full tank and driver,

I don't smog the car. Its not registered in california so I don't comply.

I got the ET and trap speed from a gps tracker. So you can probably give or take 5mph.

I was told by a lot of people that my combo made no sense. Most of them have retracted their comments

My roomate has a 2005 v6 ranger and he hates that my hotrod is better on gas than his late model v6 truck. We laugh about it alot.

 

Being as its an EFI BBC bet its a hell of a lot of fun.

Like to see how the gps compares to a time slip though just dont see 127 with that. Maybe 117? Doesnt matter though you got a nice ride that sure surprises a lot of people

 

Yeah its alot of fun. Little tempermental and tricky to drive at times but a lot of fun nonetheless.

There aren't any drag strips in the local area so getting a time slip is a low priority for me. It would be interesting to see what it puts down.

 

A built t56 and some gears and that would be a killer combo.