Toss Up

[1978ScottsDale]

Im in a real bind here. Im at the point of throwing my motor out and starting new or? rebuilding it and paying for it? What do i do here. im not looking at building anything big here just something to go out and mud race with. Its a 76 500 i have a edelbrock intake a 750cfm carb headers. 120cc heads. I want to put forged rods/pistons. and a cam. maybe if there time also put valves into the heads.

[Vern]

Sorry I don't understand. What is your question?

[STDog]

Im in a real bind here. Im at the point of throwing my motor out and starting new or? rebuilding it and paying for it?

Did I miss something?

What happened to your 500?

[1978ScottsDale]

sorry about that, i spun at least 4 rod bearings that i know of so far and im also out a crank.

[STDog]

sorry about that, i spun at least 4 rod bearings that i know of so far and im also out a crank.

Bad oil pump?

[dave_brode]

1978ScottsDale,

Was it a fresh engine? Any idea what went wrong?

Unless the block's crank line is fubar, you could use the block over.
Make SURE to tank it, and clean it well to get all the grit out. Behind tha cam bearings too.

Depending on how far your crank was "turned" while running, it might be save-able by grinding it to 2.375" on the rod journals. If it would take a normal grind to 2.375", you could use stock 440 mopar rods. They are 6.76" long. They could be bushed to allow a caddy piston to be used, as long as the piston is set up for floating pins [such as the KBs and E-bay Ross are].

If the journals with the spun bearings are ground way down, you might have to offset grind a wee bit, depending on how much is there to work with.

The mopar rods are wider. Afaik, normally the crank journal is made to fit them. [flame proof suit on here]: However, you *could* narrow the rods instead. That's a simple matter, as is cutting the bearings narrower. Probably less money than having the crank's jornals widened.

If you can find another 500 engine or crank cheap, I'd do that. Much cheaper in the long run. A stock crank could use 6.735" olds rods and caddy pistons. Much simpler build. Fyi - I have one seat of 6.735" olds rods for sale. Ping me if interested.

As far as heads, If I was building a N/A'd puller, I'd use 76cc heads for sure, as the compression should help.

If you post with your budget, I'm sure that you'd get some more opinions on which direction to go.
Dave
p.s. - I've always wished that they had a low buck 2wd class for pickups around here. I'd build one with a caddy. A few years ago I had a beater 2wd 500/switch pitch TH400 powered '71 chevy camper C-20 that would have been perfect [with a better engine]. 4x4 stuff cost too much for my cheap ass.


"]Im in a real bind here. Im at the point of throwing my motor out and starting new or? rebuilding it and paying for it? What do i do here. im not looking at building anything big here just something to go out and mud race with. Its a 76 500 i have a edelbrock intake a 750cfm carb headers. 120cc heads. I want to put forged rods/pistons. and a cam. maybe if there time also put valves into the heads.[/quote]

[bondsman]

if you dont mind spending a little more money at napa auto
a turned crank for the caddy is 175.00 dollars with no core. got one
from napa when i rebuilt my caddy. just a little more money than a
machine shop but warranteed and came with rod and main bearings.

[dave_brode]

bondsman/All,

No offense meant to the poster or NAPA, but be very careful when buying a "kit" crank, anywhere. They often are welded up cores that they've taken in on trade. Look really closely at all the journals for signs of welding. They often have small cracks in said weld[s]. On the other hand, you *might* get lucky and get one that didn't require welding.

If your crank is grind-able [w/o welding], imo, you're better off to have it ground. Esp if yours is std now, and just needs a .010/.010" clean up. The kits are often .020" or .030" under.
Dave


"]if you dont mind spending a little more money at napa auto
a turned crank for the caddy is 175.00 dollars with no core. got one
from napa when i rebuilt my caddy. just a little more money than a
machine shop but warranteed and came with rod and main bearings.[/quote]

[1978ScottsDale]

Im really wanting to do this. Just getting opinions still. What kind of power should this motor make? I think ill use .100 454 flat tops. Forged from venolie. The olds rods. Then if i have money put the 2.11 1.77 valves in the heads.
That aint enough bring on the spray :twisted:

[dave_brode]

1978ScottsDale,

Just so you know for sure: The 454 pistons require 7" olds rods.
You could get around 9-1 with a flat top, tight quench and maybe a
little head cut with 120cc heads.

A 76cc head and ebay Ross caddy forgings would make more power,
sunce those heads are a bit better, and a 26 or so cc dished piston would be at 10-1 or so. The for caddy pistons would work with 6.735" olds rods, with a little more deck cut for tight quench.

If you don't have funds for good valvetrain, you'll need to stay conservative on the cam to allow stock rockers to live.

If you are bucks down, .060" flat Speedpro 454 forged pistons would work with a real nice block [that'll clean up at 4.310"]. The speedpros are way cheaper than Venolia, etc. Not as good though, and maybe heavier.

In any case, you'll need a good 2.5" journal for the olds rods. Same bearing as caddy.
Dave



"]Im really wanting to do this. Just getting opinions still. What kind of power should this motor make? I think ill use .100 454 flat tops. Forged from venolie. The olds rods. Then if i have money put the 2.11 1.77 valves in the heads.
That aint enough bring on the spray :twisted:[/quote]

[MilesO]

You may be able to save some worthwhile money by using KB-780 Forged BBC piston with your 7" Olds rods.

Miles

[dave_brode]

Hi Miles,

Interesting. I didn't know that they offered the BBCs in forgings. Good to know. I can't get their site to load today, but I'll ASSuME that they offer that piston up to 4.350".
Thanks.
Dave



O"]You may be able to save some worthwhile money by using KB-780 Forged BBC piston with your 7" Olds rods.

Miles[/quote]

[Mark --]

FWIW,

I had problems with my Pulling Truck engine (500) because I took short-cuts. Make sure you start with a clean block and good crank spec's. Also make sure you have a Proper oil pump gasket

I use a stock bottom end with extra side clearence on the rods. It's holding together well now that I took the time to make sure of the basic things such as metioned above. :wink:

Mark --

[dave_brode]

Scotts,

Good advice, imo. I'd probably run stock or olds rods at .040" or so side clearance, but for sure, no more than .028".
Dave

FWIW,

I had problems with my Pulling Truck engine (500) because I took short-cuts. Make sure you start with a clean block and good crank spec's. Also make sure you have a Proper oil pump gasket

I use a stock bottom end with extra side clearence on the rods. It's holding together well now that I took the time to make sure of the basic things such as metioned above. :wink:

Mark --

[MilesO]

Hi Dave,
Yes, + .100 size is available in the KB-780. You will find it listed in the Piston, then Forged, dropdown windows.

Miles

[cadillac512]

Miles-
Have you seen any prices for the KB 780's? Not sure where to look..... :?:
Terry

[dave_brode]

Miles,

I see that they have flat top 454s, up to 4.350" in 1.270", 1.395", 1.520" and 1.645", AND 1.765" compression distances [would work in with a 472 crank and 7" rods].

Also flat top 4.446" in all those but the 1.765".

No dished blower pistons in their forged line though. Too bad, as some of us have looked at the dished blower KBs for a 10.8-1 to 11-1 combo with 76cc heads.
Dave

O"]Hi Dave,
Yes, + .100 size is available in the KB-780. You will find it listed in the Piston, then Forged, dropdown windows.

Miles[/quote]

[MilesO]

Terry,
I have not gotten a firm price on the 780's but I would be surprised if they were anywhere near the price of Venolia's.

Dave,
Yes, isn't the selection just wonderful, makes you want to build several .. and, offers the opportunity to use some really long rods..7.5"
will work..

Miles

[dave_brode]

Terry/Miles,

Yes, many neat possible combos. Too bad that the long rods are pricey.
The 1.765" tall ones would work with a 6.8" BBC rod and 4.530" or so stroke, for a 538" at 4.350", [depending on block's deck hiegth].
Dave
cheap sob


I have not gotten a firm price on the 780's but I would be surprised if they were anywhere near the price of Venolia's.

Dave,
Yes, isn't the selection just wonderful, makes you want to build several .. and, offers the opportunity to use some really long rods..7.5"
will work..

Miles[/b][/quote]

[1978ScottsDale]

So i am thnking at this point is to go BIG or go home.
Offset grind the crank for 4.5 stroke, take the journals down to 2.2 and use big chevy 6.8" rods.
Use a 1.75 piston. As for bore not sure yet.
Can you go .090 over on these without having big troubles?.
And as for the heads there still up in the air. :twisted:

[dave_brode]

1978ScottsDale,

A 4.5" stroke would be a .196" increase. At TDC, the big end's C/L will move up .98" [.196/2 = .98"]. Add that to the .050" longer than stock rod, and you get .148". Using 1.910" for stock C.H. : 1.910" - .148" = 1.762".

Fyi - KB has a forged flat top BBC piston with a 1.76" C.H. It's available up to 4.350", afaik. That'd give you a 535". A bigger bore would get you more, but you'd have to step up to forgings that are no doubt more costly than the forged KBs. Custom, perhaps.

With all of that said, most experts don't like a 2.2" journal, as they claim it makes the crank weaker, due to the reduced overlap. \

As far as the bore, afaik, even up to +.200" over isn't a big deal, with a block fill. Afaik, the apx $14 each Corteco gaskets will take up to 4.380" or *maybe* 4.390". Anything bigger will require require either o-rings and copper, and block machining for them, or pricey custom big bore composite gaskets that some of the vendors offer.

Fyi - a 4.466" [502BBC] piston will work with 7" olds rods and a 500 crank, for a 539". Afaik, a moderate power level deal should live ok on a 1/2 block fill at 4.466".

Dave

p.s. - An offset grind job on the crank will cost you pretty big. if you are serious, I have a set of new in box 6.8" Eagle BBC H beam rods that I'll take $325 for. A stroker is on my wish list, but pockets are empty.
p.p.s. If the stock crank/stroke, 7" rod deal looks good to you, I also have a new, never used set of 502" BBC pistons that I'll take $300 for.




"]So i am thnking at this point is to go BIG or go home.
Offset grind the crank for 4.5 stroke, take the journals down to 2.2 and use big chevy 6.8" rods.
Use a 1.75 piston. As for bore not sure yet.
Can you go .090 over on these without having big troubles?.
And as for the heads there still up in the air. :twisted:[/quote]