331 stroker block advice...

[Mike Drew]

Hi guys,

No direct GT40 content, but there is relevance to GT40 engines generally, so read on....

So, my GT350 clone is now into the seventh year of its six-month restoration (!) but it's finally moving forward. The long pole in the tent has been the engine rebuild. Long, sad story involving a dishonorable engine builder who took money to do the job, but never delivered, and eventually drank himself to death.

The job is now in the hands of a reputable guy, and he's discovered that the '68 Mexican 302 block that the drunk had provided (and charged me for) is AFU. Apparently he didn't bore it properly so the bores are oval. It can only be salvaged by boring it to .040 over and buying new pistons (to replace the brand new .030 pistons that the drunk also provided (and charged me for)).

So, the questions are these:

Should I be seeking new pistons in an effort to salvage this desirable block, or should I instead be seeking a new block to take advantage of my existing Scat forged .030 over 331 stroker kit?

And if I am to get a new block, should I be satisfied with a regular '69-70 302 block, or a new Ford block, or a DART block, or ??? Cost is an issue; I'd also like to retain the stock Z-bar clutch system without hokey bolt-on adapters, as I have heard about reliability issues with those things.

The motor will be using a hydraulic roller cam, AFR heads, and will hopefully be producing in the 430-450 hp range.

Confer upon me your words of wisdom on these matters!

Thanks!

 

[Jim Rosenthal]

Are they certain that it CAN be salvaged with an .040 overbore? And can those blocks be bored .040? I thought .030 was the limit. I know Mexico blocks are valuable, but by the time you've possibly sleeved and bored this one, you might be at the same price of a new block. If getting a new one, I would get the best Ford MS block I could afford. From Ford.

 

[Rick Muck- Mark IV]

I would not go .040 even if the block will support it (and the only way to know is to sonic test) as you will find it will run much hotter and likely have hot spots where the coolant will steam.

The Ford Racing "Boss 302" block is a very good way to go, strong, reasonable on price and the bottom end is stout. It will be the basis of the motor for my GT.

 

[David in Durango]

Mike,
the Dart (ford boss 302?) w/ 8.2 deck and 4.125 bore could give you 363ish cubes. I've never heard anything bad about the Dart blocks. the above comment about hot spots and sonic checking are VERY worth considering. I'd ask Dan, as he has hands-on experience (at least more than I have).
I'm a fan of more cubes. Less stress at same hp level, you know.

Has it really been that long? whew.

good luck.

 

[Mike Drew]

The Ford Racing "Boss 302" block is a very good way to go, strong, reasonable on price and the bottom end is stout. It will be the basis of the motor for my GT.

In looking at the Ford Racing website,

Ford Racing Performance Parts

the block looks appealing, BUT they say:

Designed for M-6049-X306//X307/C3/D3/Z304DA cylinder heads.

Not designed for production 302/351W or M-6049-Y302/Y303/X302/X303/X304/X305 cylinder heads.

=========

So, this block is not compatible with production heads???? I have AFR 185 heads, which are a direct swap for production heads, which in turn would cause me to question if they would be useable with this block?

Or is that 'not designed' crap just designed to get you to buy Ford heads instead of aftermarket heads???

Oh, and the website makes no mention of provisions for clutch lever mounting--are the new Boss blocks truly updated versions of the original Boss block (with a boss for the clutch lever) or are they 5.0 style, lacking that important feature?

 

[Rick Muck- Mark IV]

In looking at the Ford Racing website,

Ford Racing Performance Parts

the block looks appealing, BUT they say:

Designed for M-6049-X306//X307/C3/D3/Z304DA cylinder heads.

Not designed for production 302/351W or M-6049-Y302/Y303/X302/X303/X304/X305 cylinder heads.

=========

Or is that 'not designed' crap just designed to get you to buy Ford heads instead of aftermarket heads???

QUOTE]

The new "Boss" block works with most all heads as far as I know. It is designed for Windsor type heads rather than the 69-70 Boss Cleveland units. I have not heard of anyone having issues with heads on thios block.

 

[Jim Rosenthal]

It's too bad about the damaged Mexico block- they are hard to find. It could be sleeved, but to build a hi-performance engine you are better off with a new Boss block. And sleeving and remachining the 302 would cost nearly as much, wouldn't it?

 

[Gus Richmond]

Mike,
Yes, the new Boss block does have a boss for the clutch lever.

 

[Mike Drew]

Thanks guys--just ordered a new Boss 302 block.

Anybody have a need for a slightly used Mexican 302 block bored .033 over? :laugh:

 

[colin artus]

Well the block may be FUBAR but the main caps are worth about $200. Pity I'm over here and you're over there, as I've got a Mexican block that is missing I'ts caps.

 

[EGLITOM]

In looking at the Ford Racing website,

Ford Racing Performance Parts

the block looks appealing, BUT they say:

Designed for M-6049-X306//X307/C3/D3/Z304DA cylinder heads.

Not designed for production 302/351W or M-6049-Y302/Y303/X302/X303/X304/X305 cylinder heads.

=========

Or is that 'not designed' crap just designed to get you to buy Ford heads instead of aftermarket heads???

QUOTE]

The new "Boss" block works with most all heads as far as I know. It is designed for Windsor type heads rather than the 69-70 Boss Cleveland units. I have not heard of anyone having issues with heads on thios block.

my 331 is based on the new boss block and is using Edelbrock victor jr. heads

TOM

 

[DBLDREW]

I've run .040 on several motors and they have held up fine (with lots of nos going through), I've known people who have gone up to .060 as well. Should of listened to your machinist rather then random people on a forum and just went .040 and called it a day, could of saved some money as well..

 

[Mike Drew]

You should of listened to your machinist rather then random people on a forum and just went .040 and called it a day, could of saved some money as well..

...says some random guy on a forum.

Just FYI, I consulted with a lot more people than just the random people on this forum. I'm fortunate enough to enjoy friendships with some very knowledgeable people (far moreso than I am) who work in the industry; one of them has been Jack Roush's right-hand-man since 1973. To a man, each one said that for the kind of power and use I'm expecting, I would be running the risk of problems with a .040 over Mexican block, but that a Boss or DART block would alleviate all such concerns.

One engine blowup would more than wipe out whatever cost savings would be associated with keeping my existing block. After I sell the old block (which is perfectly good for a stout street engine), the new one will only wind up costing me $1000-1200 or so, which is cheap for peace of mind.

 

[Gus Richmond]

Hi Mike,
Any chance of giving a run down on what gear you are putting in/on the block?
what size AFR heads, what cam grind, manifold, EFI and ECU etc?
photos???
Hope Im not asking to much? I have a new Boss block and a coast high performance 331 kit forged steel etc. Not yet sure on the rest of the bits.....
Kind regards, Gus.

 

[Keith]

Hi Mike,
Any chance of giving a run down on what gear you are putting in/on the block?
what size AFR heads, what cam grind, manifold, EFI and ECU etc?
photos???
Hope Im not asking to much? I have a new Boss block and a coast high performance 331 kit forged steel etc. Not yet sure on the rest of the bits.....
Kind regards, Gus.

Gus, sorry mate, I believe you are far too random to have this kind of sensitive information ....

 

[Mike Drew]

Hi Mike,
Any chance of giving a run down on what gear you are putting in/on the block?
what size AFR heads, what cam grind, manifold, EFI and ECU etc?
photos???
Hope Im not asking to much? I have a new Boss block and a coast high performance 331 kit forged steel etc. Not yet sure on the rest of the bits.....
Kind regards, Gus.

Gus, great minds think alike! :laugh: The foundation of my motor is the same CHP (Scat) 331 forged kit with flat-top pistons.

I'm using AFR 185 non-emission heads with uprated valve springs:

Air Flow Research

and Scorpion roller rockers, with Trend pushrods.

The cam is a custom grind from an outfit I'd never heard of, Anderson Ford Motorsport:

Anderson Ford Motorsport

Five years ago when I started this engine project, AFM was making a name for themselves in the middle of the country. They specialize in hydraulic roller camshafts with a more aggressive lobe design; typically an AFM cam with identical numbers to a Crane, Crower etc. cam will make a bit more power due to the superior lobe design--or so I was told by the Very Smart Guy I was consulting with in the design of this engine (Dan Jones).

Here is the cam card:

This camshaft uses the later 5.0/351W firing order as opposed to the 1960s 289/302 firing order.

I'm using the standard Edelbrock Victor Junior intake, topped with a flowed Holley 700 CFM double-pumper carburetor. I have a Ford distributor equipped with a Pertronix Ignitor which has served me very well in the past, so I'm recycling that, along with the Edelbrock water pump.

I had an Aviaid 9.5 quart racing oil pan, but it just hung down too low and occasionally dragged on the ground, so I sold that to a vintage racer and replaced it with a 6.5 quart Aviaid pan, giving me all the advantages of oil control etc. with slightly less volume, but more ground clearance. After all, all the oil in the world does you no good if it's all dumped on the ground behind you! :laugh:

I've got an Earl's air-to-oil cooler mounted up front with an Earl's thermostatic sandwich adapter, so that the temperature is well-controlled.

And now, all these bits are going into a shiny new Ford Racing Boss block. Hopefully I'll have photos and dyno results to share in the next few weeks. :thumbsup:

 

[Gus Richmond]

Thanks Mike.
Much appreciated.