[Formulajones]

The AFR's I have address that pretty well. There isn't too much difference in flow between the runners. I'll have to find the flow sheets for the numbers to see exactly how much.

[Formulajones]

Originally Posted by Lee

Cleveland = 9.2" deck height
351 Windsor = 9.5" deck height

When I built my Falcon wagon, my first choice was to put a stroked 429/460 in it, most likely with Kaase P-51 heads. After a lot of searching, I could find no decent headers that would fit. There was also less room between the firewall and core support than I had expected, and getting a decent sized radiator became a concern.

Second choice was a CHI-headed Windsor. Then I met some people who were involved in the EMC, and they let me know how much work/epoxy were used on the CHI-headed EMC entries at the time...

I ended up with an AFR headed Windsor. It was fun. Over 2-tons, pump gas, ran 7.0's n/a. I should have built it with more stroke, but was being conservative.

A friend has an iron headed 496 BBC in an early 70's Corvette. 3.08 gears, HR cam, really mild converter. GORGEOUS car. VORTECPRO in Colorado built the motor. I think my buddy paid about 7500 for it, complete. It run 10.50's. He used to be a Pontiac guy, btw. https://youtu.be/zNhta8QBOnw

Gettin' it done with 3.08 gears, that's pretty cool.

[shaker455]

Originally Posted by 77 TRASHCAN

Thanks, I wasn't thinking...again.
I wonder, though if the aftermarket heads solved the un-even flow characteristics of the BBC, Don't remember which is which, two ports have great flow, two crash into the cyl wall, slowing them down...The 460 and 351C heads do not have this issue

I'm not sure but I'll ask.
I actually have a 496 BBC coming here that I might re-tool for my 70' Camaro and the heads are World Products Iron with 320cc runners #030620.

[Skip Fix]

Lee what rear does he have still the 10 bolt IRS? An old buddy from Austin has one of the Tom's Differentials modified 12 bolt chunks in his small tire class car.

[Lee]

Originally Posted by Skip Fix

Lee what rear does he have still the 10 bolt IRS? An old buddy from Austin has one of the Tom's Differentials modified 12 bolt chunks in his small tire class car.

Skip, go to http://www.amosauto.com/alans-vette/ for a lot of info on the car. Rear end info towards the bottom.

You may have met Alan back in the 90's/early00's. He had a black '77/78 T/A, 400 UD 288/296 H10, with Butler ported 16 D-ports back then, and raced in Baytown rather often. His T/A was always a few tenths slower than my '67 :-)

[Skip Fix]

Looks like he used some of Tom's parts to get more spline count.

[Ponchy]

61-63,

I don't know where I gleaned this info, but whenever I "build" a BBC on the calculator, I always assume a stock cr of 7.5:1....so if they ended up at 8.2:1, you gotta realize that engine is already realizing a 2.5-3% increase in power, just due to the change in cr, alone.
What floors me is they got 335HP on a STOCK 454.
That's pretty amazing,

[61-63]

I've never built a bbc on desktop dyno, or a 429 Ford, which I also really like just looking at the bore/stroke/valve sizes, I need to do that. I've got a '67 Fairlane I would like to do something with some day and putting a 429 in it is one possibility. We had a 34' motor home at one time and it had a carbureted 460 in it which pulled that thing anywhere no problem, Those big blocks no matter who made it produced lots of grunt.

[Ponchy]

Nice thing about a 385 series Ford...biggest bottom end ever put in a car.
Those engines were designed for NASCAR and it shows.
Main cps look like they came out of a 6-71. Not a joke.

[Me Notyou]

Originally Posted by Cliff R

The new build made LESS power in the "normal" driving range and didn't start showing it's colors to out past 3200rpms or so. A nice domed piston to increase compression would have nicely offset those losses and put it on par with the original configuration.

I would also imagine the build didn't make much vacuum at idle, and would have required a LOT of initial timing and idle fuel to be happy at that compression ratio.

We did a 455 here a few years ago, just assembled it and didn't choose all the parts. The owner had originally planned on using 670 heads but one was cracked, so he had already purchased dished pistons. He bought 85 cc KRE heads for it, and cam nearly identical to the one used in the BBC build here. So it was pretty "low" compression for the OF size cam.

It made decent power, around 530hp/540tq but it was NOT happy at idle speed and a little "soggy" in the "normal" driving range once placed in the vehicle. He also had 3.55 gears and a 3200 stall converter, and still mentioned that it wasn't nearly as "strong" for "normal" driving as he had hoped for just judging the power by the "seat of his pants". He did go on to say that it just about tear his head off and throw it out the window from 3500rpms to the shift point, so no doubt low compression big CID engines can still be pretty strong runners!

We did another 455 that ended up about 9.8 to 1 compression with an OF cam in it and even that engine didn't idle nearly as well as the ones we do at 10.5 or so compression and a little "soggy" right off idle. It did fine on the dyno but after being placed in the vehicle I got it back to tighten up the distributor curve for more initial advance and added some more idle fuel to make it happier. So compression for sure is your friend with these things, unless all you are doing is looking at the dyno numbers for bragging rights......FWIW.......Cliff

How would a set of Rhoads lifters affect the streetability of an engine like that ?

[PunchT37]

Originally Posted by Ponchy

Nice thing about a 385 series Ford...biggest bottom end ever put in a car.
Those engines were designed for NASCAR and it shows.
Main cps look like they came out of a 6-71. Not a joke.

Yeah, and the 2.5 inch rod journals. They look like a sbc main.

[Ponchy]

Notice the size relationship between this cap and the guy's hands...



...that's a 385 series rear main. Those things are massive!


Ponchy

[dmac]

Originally Posted by Ponchy

Notice the size relationship between this cap and the guy's hands...



...that's a 385 series rear main. Those things are massive!


Ponchy

If those are Trump's hands, I'd guess about 4-5 inches across.


Sorry- just got off a political website.

[MVR]

Hi there,

I realize the last post was 4 years ago but hopefully people are still around.

Reading through this thread, it's obvious that there's a tremendous amount of knowledge amongst the posters so I was hoping to pick some brains.

I am building a 454 that is bored .030 over. It was partially assembled when I purchased it so I'm working with somebody else's vision on this

It has GM 3872702 heads, 98cc closed ports, 260cc intake runners
Comp Cam Thumpr: 243/257, .522 lift, 107 LSA.
Edelbrock Performer 2.0 intake.

When I do the calculations, I get a 9.20 CR (with flat top pistons)

In your opinion, will this combination produce decent (450+) HP or should I not even bother with these heads and go for a set of aftermarket ones immediately?

I will be using it as a street car predominantly so I don't need monster HP but I also don't want to end up with a 'slug' as somebody called it.


Thanks,
Martin

[25stevem]

Those heads in stock form produce 235 intake cfm at .500” lift and yes that’s enough flow to make 450 hp from that 454 motor, my concern in getting that done thought is that Cams intake duration and having under 9.5 compression.

[Cliff R]

I would use the heads you have but that cam is not a good choice for what you are doing. You simply don't have enough compression to effectively use it. I'd look for something with about 15-20 degrees less duration @ .050" on a much wider LSA......

[MVR]

Thanks for the responses.

I was wondering if any thought was given to putting these parts together but maybe not too much it seems.

What happens if I increase CR? I found some Speed Pro domed pistons (L2399AF, -13.8cc) that would bring compression up to 10.8. Will the camshaft perform well under these circumstances and what part would become the limiting factor? The flowrate on the heads probably?

Thanks

[Ponchy]

Increased CR increases engine efficiency.
The old rule of thumb says that each point of compression increase is worth 4%-6% increase in HP.
When calculating, I usually err on the low side and just use the 4% figure.

[Cliff R]

That old "rule of thumb" is actually highly inaccurate in the real World of things although accurate IF that's all you were doing with the engine. Increasing compression by a full point allows and almost mandates another 10 degrees in duration from the cam. This will have the higher compression engine on par with the lower one at idle and low RPM's, but making a LOT more than 4 percent more power upper mid-range and top end plus quite a bit more average power. If one understands this, compression becomes your friend with these things even though there is a proverbial "brick wall" of 9.5 to 1 compression for pump gas that has been regurgitated for at least two decades now on these Forums.....FWIW....

[Stan Weiss]

Originally Posted by Ponchy

Increased CR increases engine efficiency.
The old rule of thumb says that each point of compression increase is worth 4%-6% increase in HP.
When calculating, I usually err on the low side and just use the 4% figure.

You might see that going from 7.5:1 to 8.5:1 but much less then that going from 14.5:1 to 15.5:1

Stan