Ford Big Block - Opinons Sought

[Ron Earp]

I know this isn't an engine for GT40 application but there are a lot of smart folks on this forum. Mostly. Well, a few...

I’m slowly assembling parts for a 385-series big block for my Torino. I’ve got a good Ford builder that is local to me and he knows his stuff well. But, he won’t tell me what to build as he likes to make sure the customer knows what s/he is getting into. <o></o>
<o> </o>
The intended use for the car is simply a street machine with a bent toward road course work. Not wheel to wheel racing mind you, but club track days. As such the car will be built with various components to make it safe, handle, stop, and of course go. It needs to do the things big blocks do - make a lot of noise, scare women and children, and quite naturally be reliable.<o></o>
<o> </o>
The cylinder heads have been decided on, some aluminum Super Cobra Jet heads. The builder is very familiar with them and feels confident he can make them do whatever we want from mild to wild The block will be a production block, not an SVO block. We’ll be running a carb and most likely a solid roller cam. A forged crank and rods will be used.<o></o>
<o> </o>
What isn’t decided is displacement. Rick has built pretty much all sizes of 385 motors up to 600 inches and they’ve been used mainly in drag cars and mud trucks. With the parts choices and prices it is a fairly simple thing to build a high quality 550+ inch stroker. Sort of hard to resist actually and makes you wonder why anyone would mess around with small multivalve/multicam engines with turbos and superchargers.
<o> </o>
But I need to decide on a displacement that will do what I want. I want it to have plenty of power for a 3600 lb car. It needs to turn RPM, around 7k. I’m going to keep the Toploader and that means no OD top gear. I don’t want to have to be lifting on the straight at 6000 RPM because the engine won’t turn and I’m not planning on running a numerically low ring and pinion.<o></o>
<o> </o>
There are many engine bore/stroke combinations but here are some common ones in various bore dimensions. Data shows stroke, cubic inches, and bore/stroke ratio:<o></o>
<o> </o>
Using a 4.360 Bore<o></o>
3.85” 460CI 1.13<o></o>
4.15” 503CI 1.06<o></o>
4.50” 546CI 0.98<o></o>
<o> </o>
Using a 4.450 Bore<o></o>
3.85” 480CI 1.16<o></o>
4.15” 517CI 1.07<o></o>
4.50” 561CI 0.99<o></o>
<o> </o>
One part of me is tempted to go with the 3.85” stroke because I feel it’ll rev better. I also feel that the “small” engine might not have the propensity to produce gobs of possibly useless hp and torque. Plus, if you can’t get it done with 460-480 inches does it need doing anyway?<o></o>
<o> </o>
But the better half of me says more is better. If 480” is good, 560” must be a lot better. The guys that run some the large 385-series strokers rev the hell out of them, 8-9k in some of these things and simply hold their foot down until the motor gets done whatever needs doing. So the “revability” and “breakability” might all be some theoretical conjecture that while true might be slightly different in application.<o></o>
<o> </o>
So I could compromise and use a 4.150” stroke and sort of be middle of the road. But that would kind of stink to have some Bowtie guy to show up with his 572” motor, now wouldn’t it?<o></o>

 

[WEGENER Engineering]

I do not know anything about late model Ford engines but I was told once that the 385 series is essentially a big block chevy with its porcupine valves.
So closely was it supposedly copied that even the valve cover gaskets are the same.
I do not know if any of that is true but if it is one could look towards competitive BBC powered cars and see what displacement and rod ratio they are running.
When we were running Chryslers Ed Pink told me once that the rod ratio determines the responsiveness or laziness of an engine and that road race engines require a different rod length than drag motors.
This will be an interesting thread to watch.

 

[Terry Oxandale]

In your options, are you looking at rod length/stroke ratios as well. When I had the 289 in my 240, it was a little high-strung, and awesome on the track in that 8 grand shifts were not a problem, and overall, the torque came in so high that traction was not a big issue, BUT, when I went to the 383 (stroked 351W with the longest RL/S ratio, it transformed the car into a beast, and still allowed a 7500 shift point (girdle and all the usual, but economic enhancements). I'm a big fan big bore/ long rod combinations.

 

[Ron Earp]

A few interesting tidbits of 460 motor info here:

BB Chevy/Ford comparison:
Advantages of Ford Over Chevy

Info on crank overlap:
Crankshaft Journal Overlap Drawings

So closely was it supposedly copied that even the valve cover gaskets are the same.
I do not know if any of that is true

It doesn't appear like a whole lot of copying went on. Ford needed a replacement for the farm engine that required less time to assemble and could handle larger displacement. Compared with Chevy's 454 inch motor the big block 460 has a shorter stroke and larger bore. So it doesn't appear they copied Chevy's architecture too closely. They did incorporate canted valves but that was already coming in engine designs from all of the big three and it appears that Chevy wasn't the first with that feature. A 460 nut turned me on to this orphaned "poly angle" or "poly spherical" 318:

http://www.geocities.com/polyman64/about.html

Had canted valves and was produced from 1956 - 1966.

It is a shame the 385 series came out when it did and never really saw performance development in cars. There are a lot of parts available from them now given that they are arguably one of the most plentiful and least expensive bases to make monster motors from out of the big three.

When is someone going to put one in a GT40? They are still smaller than the Ford mod motors and some of the other things being kicked around, like AMG MB V8s....and they'll make a lot more power. New transaxle anyone?

 

[Randy V]

I have to tell you that I'm not a huge fan of the 385 series engines..

I feel they are fine for a truck or school-bus and are in it for the long haul in those high torque situations - but unless you spend a lot of money on them - they just aren't a "fast" engine - nor are they high revving (out of the box)..

Of course money and availability of parts changes a lot... How fast can you afford to go - this is the order of the day for the 385 (again - my opinion)..

A couple of questions -

1) Have you considered a Stroked Windsor?
2) Have you found headers for this conversion? Many cars of the early to mid 70's were still "rear steer" cars (steering knuckles are behind the front axle centerline) and building headers for these cars is exceedingly difficult.

 

[egoman/ Shawn Wedge]

I think one of the main reasons they are not found in gt40s is that they are really heavy. At least 2 hundred pounds dressed out more than a 302 based engine. Lots of people here talk about not needing excessive power due to the light weight of a 40. ...........Mind you with the aluminun blocks ant the new Kasse boss nine conversion heads. Hmmmm.

 

[Ron Earp]

I have to tell you that I'm not a huge fan of the 385 series engines..

I feel they are fine for a truck or school-bus and are in it for the long haul in those high torque situations - but unless you spend a lot of money on them - they just aren't a "fast" engine - nor are they high revving (out of the box)..

Well of course, in stock configurations and using stock heads they are not great motors. But with aftermarket goodies, they are quite strong and they do rev - I think a 460 has a more favorable rod ratio than the windsor strokers. Along with that you get more cubic inches which is a benefit if you're working with a heavy car and/or really want a lot of horsepower. Weight can be handled if you take your time with heads, flywheels, bellhousings, cranks, and so on.

Costwise they seem fairly effective. Blocks are basically free and any of them can be used as a base. You can even use a stock 460 crank and rods if you like and they do support a lot of horsepower with the right breathing apparatus. I'll keep track of the budget I put into this motor and post along on this thread. I think the hp/$ might be very surprising.

Headers are going to be a pain. There isn't anything off the shelf that is easily available even thought 429s were in 72 Torinos, but only with C6s. But, that is somewhat ok. I've got a great fellow here in town that makes race headers and he can do a really nice set for not a whole lot more than off the shelf stuff.

....Mind you with the aluminun blocks ant the new Kasse boss nine conversion heads. Hmmmm.

Engine porn. 598 inches, 902 hp at 6,800 rpm, 800 lb-ft at 5,100rpm, and frighteningly expensive I'm sure!

 

[Jac Mac]

I know this isn't an engine for GT40 application but there are a lot of smart folks on this forum. Mostly. Well, a few...

I’m slowly assembling parts for a 385-series big block for my Torino. I’ve got a good Ford builder that is local to me and he knows his stuff well. But, he won’t tell me what to build as he likes to make sure the customer knows what s/he is getting into. <o></o>
One part of me is tempted to go with the 3.85” stroke because I feel it’ll rev better. I also feel that the “small” engine might not have the propensity to produce gobs of possibly useless hp and torque. Plus, if you can’t get it done with 460-480 inches does it need doing anyway?<o></o>[/FONT]
<o> </o>
But the better half of me says more is better. If 480” is good, 560” must be a lot better. The guys that run some the large 385-series strokers rev the hell out of them, 8-9k in some of these things and simply hold their foot down until the motor gets done whatever needs doing. So the “revability” and “breakability” might all be some theoretical conjecture that while true might be slightly different in application.<o></o>
<o> </o>
So I could compromise and use a 4.150” stroke and sort of be middle of the road. But that would kind of stink to have some Bowtie guy to show up with his 572” motor, now wouldn’t it?<o></o>

You 'Really' need to get a New 'Better Half ', more in this case is probably TOO much bearing in mind the ''budget'' is not likely to extend to a dry sump for the ''road course'' part of the equation. Long strokes in these motors is a lot of metal spinning close to the oil level looking to cause trouble on a road course and by the time you fit the headers in the engine bay extra space for a decent pan will be gone.

 

[Ron Earp]

much bearing in mind the ''budget'' is not likely to extend to a dry sump for the ''road course'' part of the equation. Long strokes in these motors is a lot of metal spinning close to the oil level looking to cause trouble on a road course and by the time you fit the headers in the engine bay extra space for a decent pan will be gone.

Will this be enough?

 

[Jac Mac]

Will this be enough?

Should be, but really for that you should buy my 'highly unlikely to ever be completed' 75% P51 project and forget about the Torino, oh & you will need 'another' garage/shed, whatever you call them over there.

 

[Rick Muck- Mark IV]

OK,

Ron I'll bite. I see the dry sump drive, but what is the other lower item being driven on the other side? I love these V8 aero engine conversions. More power, better economy than dedicated "aero (Lycoming/Continental) big bore engines.

 

[Jac Mac]

Supercharger,

A Kiwi outfit spent $$ & years trying to get a setup like this approved for Ag Plane ops here in NZ, downturn in the industry & a lot of silly over engineering caused it to get put aside. We now have the same AC powered with derated Walter turbines, but a local guy is now working on a diesel V8 conversion, looks good so far.

 

[Ron Earp]

Yep. Jac Mac got it right. I found these pics and many others on a aviation website talking about auto engine power for Spad replicas.

Got the SCJ heads in today, nice!

Ron

 

[Ron Earp]

Today I picked up my 460 engine core. Price - free, just take it away. Actually found many 460s that were free. The only hindrance was the distance to go get some of them.

Here is some in car from the Robison Racing SCCA 1972 (not really, just in looks) Mercury Montego. It runs a 555 big block Ford built from a 460.

http://www.robisonracing.com/images/Lap_of_Laguna_Seca.wmv

I'll update the BB build as I make progress.

R

 

The stock blocks are good for about 800 hp. If you may want to go endurance racing, keep the stroke short to get that power - traded for valve train stress. Otherwise, the 4 to 4.3 range does not produce excessive side load on the cylinder walls and can generate lots of torque. Consider porting the heads, they can match P-51 if done right, last set Kaase did for me was 430 cfm on intake - their best yet.

 

[Andrew Robertson]

back to your original question, I think the critical part of your selection criteria might be that you want the thing to turn 7k+, but you also want it to have a good torque spread, not just maximum effort, and semi reasonable manners. I think this points you to a displacement that the SCJ heads can comfortably service 3-7k without having to use a huge cam, and it also points to a stroke that is going to be easier on parts and allow for a long rod. I'd probably go for something in the 500-510 inches range, and I'd put at least 950+ cfm of carb on a good open plenum intake.

Cheers, Andrew Robertson, New Zealand