How important is it to have a good .040 squish/quench?

Chamber shape has a lot to do with it as well ,one reason why BBB can get away with not the best quench ..now a BBC is a totally different animal and needs it bad

 

I agree with you on several fronts. My GS is lacking the "standard" torque rush because the difirential is a highway geared 2.93. If it had the Stage 1
3.64 difirential, i'am sure I would see and feel a different in car performance.

I have read all of the threads that Larry posted re Jim's experience white building Buick engines. I have learned a lot from Jim and Larry, and others on this forum.

It really helps me to understand Buick's engine design.

The big factor I now see is there are two camps of 455 engine owners.
(1) Owners of stock 455 engines.
(2) Owners of modified high HP 455 engines.

That said, I see a huge difference of how the modified high house powered 455's are built.
First, these Buick folks change out pistons and con-rods to obtain zero deck to get much better performance and HP and increased torque. Even 1000 cfm carburators.

With a stock 455 engine, one is limited to how much performance can be obtained.

These are the questions I was asking about to try and understand what everybody in the Buick work are doing.

Buick's engine design is so much different from what I know, many years ago, I build SBC engines. They if course use the standard dome pistions at 11.1/4cr. Used solid lifter cams.
The only aftermarket parts I had to add was an Offenhuser low profile tunnel ram intake manifold, a Holley double pumper carb, headman headers and a zoom 4.56 ring and pinion. This small block made in excess of 425 HP.
Not bad for seeing all internal parts were GM.
Also considering it was a 327 (non-bored), it was a screamer in my 56 Belair Chevy. This car was much faster than my Buick GS 455.
In order for me to get my 3800 pound GS up to my Chevy's performance, I would need to do some serious add-ons that go beyond Buicks stock engine configuration.
At my age, my pockets are not deep enough to have Jim build me a high performance Buick engine.
Now that a fully understand Buick engines (I think I do), I will stay with what I have and enjoy the ride and have people who see it say, "what kind of car is that"?
Where I live, it's super rare to see a 70 GS 455 Buick lol.

I like to thank everyone on the forum that have helped me, I very much appreciate it. I would sometime in the future go to BG and see some real muscle cars.

 

Yes, I finally figured that out.
The smaller 66cc combustion chamber allows more verloity and swirl to occured in the Buick engine, causing better performance and torque.

That's amazing and something I overlooked because a 454 BBC has 118 CC's in their combustion chambers. But then, they use some pistions.
Exact opposite of what Buick's engine design is.

This for me was very confusing, seeing my small Chevy heads (factory stock) are 64 CC's, only 2cc'small than a BBB.

What always amazed me, seeing a Stage 1 Buick up againisted a 454/425 HP Chevelle at the strip and the Stage 1 would dust off the Chevelle.
Wonder why people don't believe the Stage 1 is only 360 HP!
So, one has to believe, Buick has the better engine design. We know Mr. Manner said, the true HP for the Stage 1 is 376 HP.

The 454 has a 74 HP advantage over the Stage 1.
Did Chevy embellish their ho rating??? Rest my case.

 

Corrections, 450 hp for the Chevelle. They used dome pistons. Excuse my mistakes.

 

Funny too a BBC has a much larger bore space 4.84 to our 4.75 yet from the factory have a smaller bore ..bore space is a huge advantage with valve size rpm potential..they also have the advantage of cam tunnel size compared to BBB .yet in stock to mild performance they don't go as good ..
Now a full effort deal we got nothing for them ,they got it too easy with better architecture

 

I think a big issue with the LS6 454 was that the factory iron exhaust manifolds in a Chevelle were awful compared to the Vette with the same motor.
Do you think the Belair was way faster or maby it was just louder and felt quicker cause of the 4:56's. When we were young every loud car sounded fast!!

If you have a big cam in your GS like I read then you really need to put some better gears in which you know already. Till you change out the rear you really can't get to work testing and tuning on the car you want..

Wasn't there a link when your car was for sale and telling everything that was modded?

 

Great points you make.
They could have had to bigger combustion chamber with larger valves. Things like this confuse me, how the heck did their engine engineers mis this?

My best friend is a huge Chevy fan. He has a 1970 Corvette with a 454 that produces 650 HP.

When he had aluminum heads fabricated for his 454, he specified that the intake ports be machined smaller. I asked him, why would you do this?
To increase the air/fuel velocity.

I was very surprised, I don't ever remember head manufacturer producing smaller intake ports to increase velocity. It worked for him, his Vette is a screamer.

 

BBF has it even better ...bigger bore bigger cam tunnel (and will clear a 4.5 stroke) stronger block ,small combustion chamber etc etc ...the best factory platform IMO just add heads and a cam your way up on everything else ..and most importantly a 4.9 bore space

 

In some ways it's difficult to compare my 56 Belair to my Buick GS.
(1) The Chevy had a BW T-10 4-speed.
(2) The rpm shifts are much higher than the Buick, 6,500 to 6,800 rpm's.
(3) The Chevy is a lighter car.
(4) I know my Buick couldn't turn a 12.2 et.

The one major add-on I put on the SBC is the Offenhuser low profile tunnel ram manifold.
Offenhuser copied the 69 Z28 302 CanAm intake manifold.
The big difference in Offenhuser, this is a split manifold design, you can remove the top half of the manifold. Offenhuser made 3 tops, single 4 barrel, cross ram duel 4 barrels, or a 3 duce install.
I had the single 4 barrel setup for a good reason.
I started off with a 1964 Corvette 365 HP engine with the big valve heads. Back in the day Chevy installed the AFB 625 carburator. I didn't want to over carb this engine and because I also didn't have to bore it out either, cylinders were like new when I bought this engine.
I also new this manifold design would add a lot of extra HP and be a lot more efficient than what Chevy installed to obtain 365 HP.

I have to say, there is no way my Buick GS, the way it stands now would have a chance against my old Chevy.

When I street raced, 1970 to 1974, the height of the muscle car era. I used to call my mouse motor the big blocker killer.
I was able to beat 440's, 454's, 390's, 383's, 427's and 409's.
All these engines were stock out of the factory.
Never had an opportunity to race a Hemi on the street, never saw one in my area.
That was a very fun car to drive and race. Only time a broke anything was a rocket arm.
However, I got real good at changing out clutches, this car would go through a clutch every 3 months or sooner.lol

 

Hum, that cool and sounds like a terrific engine design.

 

To add. When I bought the Buick GS, the dealer and was incorrect in one area.
They quoted my Buick had a 3:63 posi differential, which unfortunately didn't have.
My Buick has been sold in its life from two different calssic car dealerships (different States). The dealership I bought it from was the second one. I found the original first dealership in N.C. and all the second dealership did was copy their Ad.
I didn't find all this out until I had the Buick put into a shop to try an fix a load of engine problems, ugh.
I had them check the differential and I even had it pulled out and sent to one of our forum members for a rebuild. It turned out to be a 2:92 diff, but it is a posi. That seems strange to me. Most 2:92's out of the factory are open. Makes me wonder if someone changed it to a posi.
I have the build sheet and the Buick was build in KC.
On the build sheet, the axle is ID'ed as OK. I found this stamped on the axle housing.
It doesn't say if it's a posi or open.
I talked with Duane on the forum and he sure it came out of the KC plant as a posi.
So, that's the good news.

 

Here's a look at this Offenhauser intake manifold. Check out the runners. You can still buy this manifold but it's super expensive.
First 3 pics are what I had.

Bottom pic is the dual carburetor version. Super cool.

 

Here's a look at this Offenhauser intake manifold. Check out the runners. You can still buy this manifold but it's super expensive.
First 3 pics are what I had.

Bottom pic is the dual carburetor version. Super cool.

 

I don’t pay too much attention to it. I’ve had some engines with the piston as far as .045” in the hole. And yet have 12:1 compression,as well as plenty of other scenarios. Have the correct cam ground. Anything on the shelf is going to come up short. They are made to appeal to the masses,but are rarely an exact fit.

 

That's amazing, 12:1 cr with pistons .045 in the hole, plus the head gasket thickness.
When I built Chevy engines I always used factory high performance cams, I figured the factory knew what they were doing.
Now days it's a toss-up what you're going to get. Cams, alum heads and compression is a real science.
It's like when companies dumped the pension plan and installed their 401 stock market retirement plan.
How many people know how to figure out the yoyo of the stock market.
My father-in-law used to say the 401 is like gambling. Get a pension if you can, at least you know what you're going to get every month.

 

Thank you Larry.
At least I haven't seen this post before, so your time is not a wast. Vet

 

Until you run your car down the track, you really don't know what it will run.

My 66 Skylark with a basically stock 71 455, reg heads, Th350 trans, 3.08 posi rear will run 13.0-13.2 depending on weather. I've calculated the compression to be about 9.3:1. It's got TA 10-1 cast pistons, stock bore, steel shim head gaskets, and a TA 288-94 cam in it. Stock cast iron exh man. An Edelbrock B4B and a 800 QJ. I think it does fairly well with as stock as it is. There really is nothing trick in my motor. If I went to a better rear gear, I'd probably knock a half sec off my time.

It's all in the combination.

Edit...

Just for reference, I had something like .035 deck to piston clearance, and then a .020 steel shim head gasket with my current setup.

These cars/engines are quicker than what they're HP rated at. It's the torque that does it.

 

I’ve been very fortunate to meet and work with some amazing people. Some of which,most have never heard of,but they are the quiet ones that actually make it happen for the bigger names taking fame. It’s been quite an experience and honor to get to develope,test,and improve some of the very parts on your cars.

 

HP is a derived number from measured torque. It is a set formula and is why the torque and HP always cross at 5250 RPM.