302 cid Small Blocks

[Clem Z.]

Re: the new C-6 engines will have full floating

bore 96.01 mm X 83.0 m stroke,9.5:1 cr,firing order 1-8-7-2-6-5-4-3, 270 hp @ 5200 rpm, 285 #ft torque @ 4000 rpm,

[Joe L.]

Re: 302 cid Small Blocks

GL-----

Yes, you're correct; I had it "reversed".

[George Daina]

Re: 302 cid Small Blocks

First of all, the racing Ford 302 (the Boss 302) has nothing in common with the standard Windsor 302 except for bore and stroke dimensions. EVERYTHING else is different: deck height, bearing sizes, rod length, head bolts, port configurations, valve arrangement, etc. They are as different as a Chevy and a Pontiac engine. The Chevy engine can be configured into a greater range of engines sizes. The Ford 302 is pretty much tapped out at 302 cu. In for production use. Yes, there are 347 stroker kits for it, but there are also 434 cu. in stroker kits for the Chevy.

Ford was able to maintain the standard Windsor 302 in production for all those years because other parameters of the engine give it decent drivability characteristics. One of the most critical factors is rod length. The Chevy 302 connecting rod length is 5.7 inches. With a 3 inch stroke, this yields a rod/stroke ratio of 1.9. Ratios above 1.8 are usually applied to high RPM race engines. Ford's 302 has a rod length of 5.090 inches yielding a rod/stroke ratio of 1.697. This allows the Ford 302 to make streetable torque more easily. The bore spacing is smaller, making the engine shorter, too. This plus the shorter rod and piston compression height permits a much lower deck, all of which makes the Ford engine a bit more compact than the Chevy equivalent. ( a consideration for production purposes). Other variables helped the Ford 302's longevity but rod/stroke ratio was a key item.

[George Daina]

Re: i used the .072 spirolocks on BBC and SBC and

You bet, it's almost an art putting in the dual spirolocks, but well worth it...bulletproof, unlike the snap rings. Took me almost 5 minutes before I got the first lock installed, same with the second, but the subsequent, all downhill, and very sore fingers.

[John M.]

Re: the new C-6 engines will have full floating

Mike,
You are sure right about the 4.8 engine! I just bought a new truck last week with one of these engines and man, will it run. The truck can't hardly spin the tires from a dead stop, but about 60-80 feet down the road the engine comes on the pipe and the rear tires go up in smoke! It easily runs as good as the 5.3 in my Tahoe and knocks down 2 MPG better mileage. If the torque converter has 500 more RPM of stall, you would hardly be able to take off from a light.

Regards, John McGraw

[Joe L.]

Re: the new C-6 engines will have full floating

John-----

Yes, GM "got it right" with the Gen III small block engine series which first appeared in the 1997 Corvette. Besides demonstrating that push rod engine architecture has a lot of life left in it, they've really "blown away" the competition as far as powerful and torquey engines are concerned. Ford, in particular, locked themselves into smaller displacement engines when they went to the OHC route for their "mainstream" V-8 engine architecture. In order to get anything near comparable power levels, they have to go to 10 cylinders. But, they can't use that in cars.

The compact, Gen III GM V-8 engine is small enough to fit into a lot of FWD platforms. You may see it soon in the Monte Carlo/Impala. Plus, the Gen IV small block is right around the corner.

I stayed with push rod technology for my driver car. I recently got a 2004 Grand Prix GTP. This car is equipped with the Series III 3800 engine. This is the engine that traces its roots back to 1964. It's, basically, the old Buick V-8 with 2 cylinders lopped off. However, it's been tremendously refined over the years. The supercharged version in my car produces 260 hp at 5,200 RPM and 280 lf/ft of torque at 3,000 RPM. It's one of the most "fun-to-drive" cars that I've ever owned, including Corvettes.

The production of the peak power and torque at relatively low RPM is one of the keys to the great performance of this engine. It produces these in the range that is NEEDED and USED. Most OHC designs need to spin higher RPM to achieve their peak power. Plus, due to the small displacements which are incumbent for most OHC engine architectures, they lack torque.

The new Chrysler 5.7 L Hemi may give GM engines a "run-for-the-money", though. Chrysler has, apparently, seen the wisdom of the push rod engine architecture.

[Mike M.]

Re: the new C-6 engines will have full floating

john: i ordered my '03 4.8L with the 5 speed manual and 4.10 rear. it comes out of the hole like a banshee. gets 21 mpg running the interstate @ 80+ mph. just love it. mike

[Clem Z.]

Re: the new C-6 engines will have full floating

when the gen III came out in 97 GM said it will meet the emissions and cafe std for the next 15 years. with the 3 valve head coming in the gen IV the power will be up 15% and the fuel milage will be better. "long live the pushrods" because the gen IV will have 24 pushrods not 16.

[Joe L.]

Re: the new C-6 engines will have full floating

clem-----

Something that I forgot to mention: GM got the best of both worlds with the 4.2 liter DOHC inline 6 cylinder used for truck applications. This engine has great power, although at a somewhat high RPM, but torque at about where you need it. They were able to do this because the L-6 architecture allowed for high displacement AND DOHC/4 valve configuration. It's still a fairly big overall "package", though, and it wasn't designed for and likely won't be used for cars (except possibly "crossover vehicles". What's a "crossover" vehicle? It's the modern-day parlance for what, in the days of body-on-frame automobile construction, was called a "station wagon"). The 4 and 5 cylinder derivatives of this engine, just coming on-line now, will be truck-only engines due to their size. We might see the DOHC 6 in a car that has not yet been approved for production. It will a retro 60's-like convertible car built on a Trailblazer chassis.

Big displacement, DOHC V-8s are a pretty-tough-nut-to-crack. They could provide the best of both world's, too, but packaging and production costs limit their application tremendously. GM tried it once with an engine called the LT-5 (remember that?). All-in-all, they couldn't "make it work" from a packaging as well as a COST standpoint. The LT-5 could, undoubtedly, have been developed to produce a lot more power and, perhaps, more than the Gen III or Gen IV, but they'd still be left with the "packaging" problem (absolutely FORGET any FWD car application) and, most especially, the cost problem, even if GM had taken over production on a larger mass-production basis. So, RIP.

[Clem Z.]

Re: the new C-6 engines will have full floating

the DOHC I-6 is so tall they run the front axle thru the oil pan on the 4 WDs. they say if they used a DOHC V-8 in the C-5 the hood would have to be so much higher that the closest spot in the road you would be 15 feet farther out. the cost of the DOHC V-8 has to be much greater from the manufacturing standpoint and the general knows how to pinch the pennies. even the new HI PERF caddy uses the ZO-6 push rod engine.

[John M.]

Re: the new C-6 engines will have full floating

Mike,
Your choice of rear end gears and transmission obviously make the engine work to it's max. My truck has a fairly shallow 3.42 rear gear and the auto overdrive automatic, but I am still impressed with it's performance.

Regards, John McGraw.

[John M.]

Re: the new C-6 engines will have full floating

Joe,
I could not agree with you more on the pushrod engine! There was a time where I resisted the move away from the old smallblock, but now believe that the Gen III smallblock is superior in all respects. I now own nothing but Gen III engines with a truck with the 4.8, my Tahoe with a 5.3, and my 59 Corvette with a 5.7 LS6 engine going in! I debated the engine choice on my 59 conversion for a long time and was really leaning to the overhead cam ZR1 engine for pure wow factor, but finally settled on an engine that I know will have plenty of parts availability in the future.

Regards, John McGraw

[Duke W.]

Re: the new C-6 engines will have full floating

I gave up on pushrod engines as dead in the seventies. Then GM reinvents them with the '90 LT1. Then they reinvent it again with the Gen III, and now Gen IV is about to be unleashed and will yield somewhere at or near 500 HP on the '06 Z06.

Wonders never cease! I'm a believer, again!

Duke

[Duke W.]

Re: the new C-6 engines will have full floating

You're truck also has a 3.06:1 first gear. The others are 1.63, 1.00, and 0.70:1.

Ratios are much wider than Corvette manuals or yore, but the broader torque bandwidth of today's engine allow wider ratio spreads for more flexibility.

Duke