Best OEM blocks???

[wjnielsen]

Sitting around BSing and bench racing... uh, I mean discussing future plans... with a couple of buddies, a question was posed: What's the best OEM block to start with for making a healthy N/A street engine?

I guess I'll need to narrow the scope a little for a sensible answer.

We were talking about building a big block with fairly modest pieces. Heads that take standard kind of valve gear (keeping rockers in the $500-700 range), OE block, probably OE crank or budget aftermarket piece, economy grade rods (Scat/Eagle?), moderate weight pistons without 'trick of the week' ring packs or off the wall custom machining, hot street or endurance racing type of solid roller cam. CR as high as pump gas would allow. Basically, a hot street piece that would be able to run every other week at the strip and hopefully get a couple years on valvesprings and maybe a bit longer between teardowns.

Being a MoPar guy, I know that a build like this (think Indy 440-1 or Edelbrock Victor heads, 400 block with 3.75-4.25" crank, short fill, aluminum main caps, girdle) could find the weak point of a block. Not necessarily WOULD break it, but certainly COULD break it. And that's after finding the good 'cold weather' 400 block, buying aftermarket caps, filling the jackets halfway up, buying a girdle, and spending $$$ on competent machine work. Lots of $$$ to pee away on a broken block...

So, the question is: for that kind of build, which blocks will be more bulletproof? Leaving the Boss 429 Chrysler Hemi, and arcane/rare/expensive stuff out of the mix, what would YOU guys build? BBC? BBF? Cleveland Ford? FE Ford? Daihatsu Charade (yeah, 993 cc's of fury, baby!)? Or is an engine like this just going to have to be built on an aftermarket block to be bulletproof, regardless of make?

-Bill

[Baprace]

bbc is your best bang for the buck, a mild 454 will produce real decent torque in street trim, I think aftermarket 7/16 rod bolts are a must for higher rpm's durability, 2 or 4 bolt mains not too important/difference on street engines at 500 hp level

[Ken_Parkman]

AMC 401. When they made the 401 it got the steel crank and good block with the big bulkheads and base. I know of a stock block and crank based combo run into the high 7's at 2700 lbs. It, the BBC, BBF, and maybe the Olds diesel based block are what I consider the best conventional (old) production engines. Of course just about anything modern benefits from modern stress design techniques and is much more capable of making power with a stock block.

[rskrause]

BBC as much for the huge availability of parts as anything else. Stock block with basic machining is plenty strong for a street/strip motor.

[LnL]

Do a search on "Jim Hand", and see what he's done with damned near all factory Pontiac parts.

Personally, I'd probably go with a 460 Ford based motor, if I were to start a new project today.

Lee

[Keith Morganstein]

It's all subjective and many blocks are good blocks.

IMHO, the Gen 6 BBC is very hard to beat for both HP/Dollar and reliability.

[347guy]

Large cubic inches from a stock 460 Ford block with no headaches.

[JBV-HEADS]

If you used the OEM parts only and added machining, then the Ford 460. It is the only one that can reach 650hp with the parts from the factory and a cam. Having said that the BBC has the aftermarket cheaper parts and can exceed that with them. It depends on what limits you place on the build. Good luck,

Joe

[Alan Roehrich]

Any decent rectangle port big block Chevy can easily reach well over 650HP with a cam. A decent 396/375 Stock engine will make 600 with only a 0.520 lift cam. A decent 427/425 will make 630. A 427/430 will make well over 650 with a stock lift .560/0.580 cam.

A tall deck 427 block will make 557 cubic inches. If you restrict the engine to factory mass produced heads and intake, say at least 1000 sets produced and installed on production cars, but allow an aftermarket rotating assembly and cam, nothing outside the Hemi can touch the big block Chevy.

The 2x4 427 Tunnel Port Ford 427 and the Max Wedge get close, mostly due to two 4 barrel intakes being available.

[JBV-HEADS]

Alan,

where are you going to pick those OEM rods up at, 50ft or are you going for the Olympic rod toss record. The BBC has most of the parts, but the rods. The Hemi would be my choice too in the hands of a good tuner. I did forget that one.

Joe

[Alan Roehrich]

Few, if any, factory rods are as strong or stronger than the 7/16" rod bolt big block Chevy "dimple" rod. There certainly is not anything Ford has to offer in a factory big block rod that can even approach the standard dimple rod with the 7/16" bolt. You can upgrade to the boron bolt if you feel the need.

Bobby DeArmond went 9.99 at over 129MPH ten years ago with a 69 Camaro 427/425 that weighed in at over 3400#. With a factory Holley 780 on a factory dual plane intake, a 0.520 lift cam, and stock rods with 3/8" rod bolts.

I've raced big block Chevy engines for over 30 years, I can't remember breaking a rod. I had 3 675HP bracket 468 engines that went 2000 passes on stock rods with 3/8" ARP 8740 bolts. We had one 850HP 468 that lived 3 years in a drag boat and ten years in various bracket cars that had stock LS-7 pistons on stock dimple rods with 7/16" bolts.

[JBV-HEADS]

You like to argue don’t you. Try to create something that is not really there, right. I have some time. What OEM build did the 7/16 dimple rod come in? The comment was OEM. Never seen a dimple rod break. You don’t get around much do you. They hate rpm and nitrous. They are worth more on Evilbay than in a race motor. Stronger rod, you named one already. My guess is that you would drown with a GM block around your neck. That’s OK. Everyone believes in something.

For me, brand doesn’t really effect my thoughts other than a cheaper way to build something or a block or head will pass tech rules. Blocks and heads are nothing more than clay to me. Something to form to circumvent a rule somewhere. I enjoy doing something new that people don’t know exist. I’m not a Ford guy, or chevy, or mopar, Toyota, Honda, although my teeth were cut on a 69 Roadrunner. That 383 didn’t last a month and in went a 440. I use what the rules allow and create what I want. And if a track will not protect me and mine from cheating. Then we are the best at that too.

Bill wanted the strongest block. I believe the Hemi (he eliminated) or 460 Ford will fit the bill the best. Since it’s pump gas, cubes must be maximized because rpm will become limited due to compression. The advantage of the 4.9 bore spacing Jon has proved over and over. It’s now 5.0 and if rules permit, going to get bigger. The 460 block will take more beating than pump gas can give it. So it is probably the best choice for what Bill has asked for.

Is there any more comments? Thanks,

Joe

[Keith Morganstein]

What OEM build did the 7/16 dimple rod come in?
Joe

Joe they came in a lot of BBC's. All the high HP like L-88, LS6, LS7 and many others. They are a strong OEM rod.


Now back to the original post that started it, the OP asked for OEM block and aftermarket components. He did not ask about ALL OEM components. He does write "Modest" "Economy" and "Budget" in the post.

We were talking about building a big block with fairly modest pieces. Heads that take standard kind of valve gear (keeping rockers in the $500-700 range), OE block, probably OE crank or budget aftermarket piece, economy grade rods (Scat/Eagle?), moderate weight pistons without 'trick of the week' ring packs or off the wall custom machining, hot street or endurance racing type of solid roller cam. CR as high as pump gas would allow. Basically, a hot street piece that would be able to run every other week at the strip and hopefully get a couple years on valvesprings and maybe a bit longer between teardowns.
-Bill

[Alan Roehrich]

OEM 7/16" dimple rods came in the 427/430 ZL-1, the 427/430 L-88, the 454 LS-7, and the 454/450 LS-6, actually.

From the Chevrolet Power Manual, 5th Edition Page 4-8 : Chevrolet high performance connecting rods are recommended for use in these engines. They are magnaflux inspected in production, plated on the pin end for floating pins, and use high alloy steel 7/16" rod bolts.

Same book, page 4-41:
3969804 Connecting rod (L-88) 7/16" bolts, floating pin
3963552 Connecting rod (LS-6) 7/16" bolts, pressed pin

I only named two rods, the rod with 7/16" rod bolts, and the rod with 3/8" rod bolts. Over all, the rod with 7/16" rod bolts is stronger than the 3/8" rod bolts.

I like to argue?

You came in with, and I quote :

If you used the OEM parts only and added machining, then the Ford 460. It is the only one that can reach 650hp with the parts from the factory and a cam.

And now you want to bring up nitrous? And then you want to accuse me of creating something that is not really there? Really?

What 460 Ford is it that you can change the cam only in and make 650HP? Remember, OEM, as it came from the factory, and you can make 650 by changing the cam?

I'm not aware of any production Ford 460 with enough compression, intake, or cylinder heads that you can change only the cam and make 650HP.

I get around plenty. I've been racing and building engines part time since 1979, and full time since 1985, except for about 5-6 years when I left due to being burned out. Even then I was still building stuff part time. Out of at least 100 big block Chevy engines I've built, I've never broken a single connecting rod, ever, not even a stock rod with 3/8" bolts.

No, no more comments to waste on you and the huge chip you tote on your shoulder.

[wjnielsen]

Hey all,

Thanks for the replies; lots to mull over.

BTW, let's all play nice here... all us American car guys need to all stick together; we'll be overrun by turbo'd JDM stuff before long...

Yeah, the Hemi, Max Wedge, side-oiler and Boss Fords probably all have really good blocks - but they're into that price range where a guy can buy aftermarket stuff that's probably at least as good.

***************

The reason the whole question comes up, is that the engine in my current toy is a BBM that's basically like what I described.
The combo is 440 Source crank/rods/pistons (KB forged?) and heads (think Edelbrock Performer), with a solid roller (262 @ .050) and tunnel ram.

Probably not going to blow itself up with raw power as it sits. On the other hand, having the heads ported, and stepping up the cam, could put this into the area where the stock blocks' weakness shows up eventually. Probably not immediately, but very possibly someday...


***************

I guess the best way to have phrased the question would have been: "for a 650+ HP N/A street build, which OEM block would you use?" Because that's a performance mark that's getting pretty acheivable for the average guy with 'bolt on' type heads and stuff.

Funny thing that the 350 Olds was mentioned. I remember reading an article about a guy using one of those in a P/S Firebird (snuck in because of the 403 engine), which he was spraying because it was a 'small block'. But, I don't think that a 350 Olds as a low-budget N/A engine is going to keep up with a BBC or BBF. Well, not in me or my buddys' wallet ranges.

As far as rods go, there are plenty of inexpensive aftermarket ones. I'd sell the good 440 6-pack or Hemi rods and buy something that's probably an improvement in strength (and certainly in weight) for similar money. I'd guess the Chev rods would probably be a similar case.

But it sounds like in the realm of "budget performance" (kind of an oxymoron, huh?), that the choice would be a 460 Ford or 454/502 Chev.

So, the 4.9" bore spacing was mentioned; what advantage does that give when using a stock block? I'd expect that the 10.3" deck would be a bigger advantage if a guy wanted to put a 4.5" crank in.

Luckily, it's not like I have to run out today and start doing anything. I'm just really looking forward to the next hot rod. I think I will always worry about laying the spurs to the current one.

-Bill