Engine Boss 302 block vs HiPo, Windsor, GT-40 for vintage racing

D K · Aug 17, 2020

Hello

I'm trying to find some info to fill in the blanks in this ambiguous rule book.

Car is a 65 and the rulebook says 289 or 302 iron block. No mention of which one exactly. Heads have to be a 20deg iron head (althgouhg some sanctioning bodies allow alum heads with a 50lb penalty).

Besides the 4 bolt mains, is there anything different on the Boss blocks? Are the heads and intakes interchangeable?
If the Boss the best option of the ones mentioned?

Many thanks in advnace.

D

7991LXnSHO · Aug 17, 2020

This should help.

Ford Boss 302 engine - Wikipedia

en.m.wikipedia.org

The blocks had higher nickel content, and Cleveland heads with a modified coolant passage. Are the canted valves in a Cleveland head what they are referring to in the 20* rule? That may rule out the vintage HO 302 (boss).

I would like to know how the 290 period Hp compares to a GT-40 (Cobra or Exploder) production engine’s output. The power and torque curves would be different, but the Gt-40’s output range could easily be changed with a different roller cam and matching springs.
.

D K · Aug 18, 2020

Thank you.

Yea, I read that article too.

I think the purpose of the 20deg rule is to keep away from the canted valves, although I'm not sure.

Right now Im trying to determine if the Boss 302 block is allowed, and if so, do the regular Windsor block heads match up? I know if you use Cleveland heads, you have to modify the coolant passages, but not sure about the Boss block/Windsor heads..

D

7991LXnSHO said:
This should help.

Ford Boss 302 engine - Wikipedia

en.m.wikipedia.org

The blocks had higher nickel content, and Cleveland heads with a modified coolant passage. Are the canted valves in a Cleveland head what they are referring to in the 20* rule? That may rule out the vintage HO 302 (boss).

I would like to know how the 290 period Hp compares to a GT-40 (Cobra or Exploder) production engine’s output. The power and torque curves would be different, but the Gt-40’s output range could easily be changed with a different roller cam and matching springs.
.

7991LXnSHO · Aug 18, 2020

I would think the cost of a genuine Boss block would be more than a better Dart block. If you are not running the modified Cleveland heads, why run the Boss block? The 2/4 bolt mains are not the weak spot.

D K · Aug 18, 2020

That;s what I'm trying to find out..

Certain clubs allow for a Dart block, so that woudl be my first choice.
Are the Boss blocks problematic? It seems you can still buy new ones from Ford. Is there a better option?

D

7991LXnSHO said:
I would think the cost of a genuine Boss block would be more than a better Dart block. If you are not running the modified Cleveland heads, why run the Boss block? The 2/4 bolt mains are not the weak spot.

zookeeper · Aug 25, 2020

I've owned a Boss block that a previous owner ran with 289 heads and intake, so I know they're identical. Aside from screw in freeze plugs and 4 bolt mains, they're the same. Not worth the money either. Spend your money on heads and intake, that's where the power is made. Look up Richard Holdner on Youtube, he's had several SBF motors go to 600 hp without failures so I think you're safe with the 380-ish hp you're most likely to see on a road race, vintage legal SBF.

D K · Aug 25, 2020

Thank you

I think I got most of it figured out...
The reason why there is not that much info out there, is that most people want to use the boss heads on a boss block for obvious reasons, so I am kind of like going backwards.

But in any case, 380 won't get me very far...I'm looking for 600+
289, Honda journals, nascar pin etc etc., should get to around 8000-8500 and get me where I need to be.

d

zookeeper said:
I've owned a Boss block that a previous owner ran with 289 heads and intake, so I know they're identical. Aside from screw in freeze plugs and 4 bolt mains, they're the same. Not worth the money either. Spend your money on heads and intake, that's where the power is made. Look up Richard Holdner on Youtube, he's had several SBF motors go to 600 hp without failures so I think you're safe with the 380-ish hp you're most likely to see on a road race, vintage legal SBF.

zookeeper · Aug 25, 2020

Wow, that sounds like a big number from a 302 inch, n/a motor. Be sure to post build pics among the way!

D K · Aug 26, 2020

Yeah...

The competitive guys are getting 580ish from a 289 and about 30-40 more from a 302.
I guess the secret sauce is spinning it to the moon

zookeeper said:
Wow, that sounds like a big number from a 302 inch, n/a motor. Be sure to post build pics among the way!

65ShelbyClone · Aug 29, 2020

D K said:
The competitive guys are getting 580ish from a 289 and about 30-40 more from a 302.

Is that what they're telling you? Keep in mind that most racers are full of s--t, especially the fast ones.

Regardless, I wouldn't go racing with a two-bolt Ford block if I could avoid it. The aftermarket "HiPo" 302 blocks that Ford used to sell can crack sometimes at the 450hp level in road racing.

D K said:
Are the Boss blocks problematic? It seems you can still buy new ones from Ford. Is there a better option?

The "Boss" block Ford sells now isn't the same one they made in '69-70; it's thicker and stronger. The only complaint I've heard is that the cylinder skirts aren't very long, but that it's not a problem with the stock stroke.

D K · Aug 29, 2020

65ShelbyClone said:
Is that what they're telling you? Keep in mind that most racers are full of s--t, especially the fast ones.

Right!....
We do have that reputation.

But in any case....its been validated (unfortunately).

When guys who are making 520-530 are being passed by on the straights, it makes it believable. Is it 100% true? who knows.....
At least that is a target I am shooting for, if I fall short, I might be at 540-550 rather than falling short of 500...

65ShelbyClone said:
Regardless, I wouldn't go racing with a two-bolt Ford block if I could avoid it. The aftermarket "HiPo" 302 blocks that Ford used to sell can crack sometimes at the 450hp level in road racing.

Definitely!

I think either the Dart or Ford Motorsports block is a starting point at a minimum.

65ShelbyClone said:
The only complaint I've heard is that the cylinder skirts aren't very long, but that it's not a problem with the stock stroke.

Luckily, that only affects the 'strokers'. For me, with a 2.87 stroke, that's not an issue and actually makes it cheaper/easier to get the block.

zookeeper · Aug 29, 2020

I know some people are getting 600 from a 347 on boost, but I’ve never heard of anyone getting it N/A from 300 inches. But Ill reserve judgement because I know there’s some smart people with deep pockets.

65ShelbyClone · Aug 29, 2020

D K said:
Right!....
We do have that reputation.

But in any case....its been validated (unfortunately).

It's only unfortunate for the people who don't figure it out. To be fair to racers, I'd do the same thing if I was one. My uncle was a boat and land speed racer and he took the other approach of just not talking about anything. He didn't talk much anyway though...

When guys who are making 520-530 are being passed by on the straights, it makes it believable. Is it 100% true? who knows.....
At least that is a target I am shooting for, if I fall short, I might be at 540-550 rather than falling short of 500...

if I was building a race program, then I'd make intelligence-gathering my new pastime. There is a surprising amount of information available just from a spectator's vantage point.

D K · Aug 31, 2020

That's pretty much what's led me here

65ShelbyClone said:
if I was building a race program, then I'd make intelligence-gathering my new pastime. There is a surprising amount of information available just from a spectator's vantage point.

D K · Aug 31, 2020

I'm no expert, but compression and rpms make miracles happen....

zookeeper said:
I know some people are getting 600 from a 347 on boost, but I’ve never heard of anyone getting it N/A from 300 inches. But Ill reserve judgement because I know there’s some smart people with deep pockets.

zookeeper · Sep 7, 2020

No kidding. Please post pics and details of your engine. I’m assuming based on your expectations that this is some sort of an unlimited class with no restrictions on heads, intakes, carbs or displacement. If that’s the case, you may be correct.

D K · Sep 8, 2020

No, not exactly...

We have a bunch of restrictions, some of them pretty stupid..

We can run aftermarket blocks and heads as long as they are iron. So either a FMPP block or a Dart.
Heads, they have to be inline, 20deg heads. Either Dart Iron Eagle or if I can find a set of high ports, I would go for those.
rotating assembly is open, I have a billet lightweight internal crank, and once I get my heads picked out, I can have set of pistons made.

Induction is a little convoluted. You can only run a dual plane, non airgap manifold and a Holley 4 barrel with 1.687 throttle.
However, some sanctioning bodies are allowing a 4 2V Weber 48IDA setup or even a dual 4bbl Holley setup.
There are guys that are making a lot of power with the basic 2 plane manifold and I'm not sure if it would make sense to have 2 different setups for different clubs.

Other than that, it's just a solid roller, shaft mounted rocker arms and fingers crossed - ti valves.

I'm at a standstill at the moment because I don't have the heads yet and can't have the pistons built until I can send them a mold. It's pretty hard to build compression out of such a small stroke, and of course a big dome is gonna limit the cam design...

zookeeper said:
No kidding. Please post pics and details of your engine. I’m assuming based on your expectations that this is some sort of an unlimited class with no restrictions on heads, intakes, carbs or displacement. If that’s the case, you may be correct.

Engine Boss 302 block vs HiPo, Windsor, GT-40 for vintage racing

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