[taff2]

ho, why not look at the early blocks? A 58-60 389 block has a bore of 4.062", you could easily sleeve it down to 4.00", drop in a lightweight 3.00" stroke billet crank, long rods with .927" SBC pin end to use off the shelf lightweight SBC pistons and light pins, properly cammed it would be a screamer, I wouldn't see a problem with 8500rpm. Nothing wrong with sleeves if they are done properly. Of course you would need all lightweight TI valvetrain pieces,5/16" stem valves etc etc (just as the high revving SBC's,SBF's need to have), build as much compression as you can if you are not limited in your fuel choices (Toluene is your friend if using pump fuel), strong pushrods-as this is where an 8500 rpm tall block will have problems (not in the 7" long con rods!).
I'm sure Steve Barcak has a few early 389 blocks around,and they are very strong. Food for thought maybe.

[hurryinhoosier62]

The only problem I can see is weight and transmission adapters. My '59 389 weighes in at 215 lbs. My '72 400 blocks weigh around 190 lbs. A Dart SBC/SBF block weighes in at 165-170 lbs. The adapters I've priced are around $790. Even though it's aluminum, it will still add weight. I would love to hear Craig Hendrickson's imput on this...

[Nicks67GTO]

I'm late to the party here but road racing is a load of fun. It's a shame more guys don't go out and run their stuff. I'm planning to run the GTO at Midwest Musclecar Challenge at Putnam Park and Optima Ultimate Street Car at Road America this year. I currently have PaulK building me a 4" stroke 400 for the upcoming season, throwing some 200tw tires on and adding an accusump. I cant wait.....

Ok carry on

[Jack Gifford]

Originally Posted by hurryinhoosier62

... My '59 389 weighes in at 215 lbs. My '72 400 blocks weigh around 190 lbs...

???

Early blocks I've had ('57, '58, '59) all weighed real close to 170 pounds (bare, no caps). I thought I also remembered weighing a 400 block at about 170, but could be wrong on that.

[hurryinhoosier62]

Originally Posted by Jack Gifford

???

Early blocks I've had ('57, '58, '59) all weighed real close to 170 pounds (bare, no caps). I thought I also remembered weighing a 400 block at about 170, but could be wrong on that.

Jack, I've still got the bill of lading from the 389 being shipped to me. The total weight was 225; 10 lbs for the pallet and 215 for the block.

[hurryinhoosier62]

Originally Posted by Jack Gifford

???

Early blocks I've had ('57, '58, '59) all weighed real close to 170 pounds (bare, no caps). I thought I also remembered weighing a 400 block at about 170, but could be wrong on that.

Jack, I've still got the bill of lading from the 389 being shipped to me. The total weight was 225; 10 lbs for the pallet and 215 for the block. Looking at the difference in main caps, bulkheads and cylinder wall thickness between the 389 and the later '72 400 blocks I own, 215 is plausible.

[taff2]

An adapter plate to mate an early type bellhousing to a late transmission is pretty easy to make yourself out of 1/4" thick T6 ali or steel, but there are drawings/plans on this site I believe, didn't Gavin from Australia and Bruce collaborate on this project? Print off a drawing and take it to your local laser/water jet cutting shop.
215 lbs for an early 389 block is still lighter than an aftermarket block,and even with 8 sleeves and machine work should work out at a reasonable cost.

[Tom Vaught]

Gavin and Bruce did collaborate on providing updated info/drawings based on work that Mark @ Luhn Performance and I identified with the Tom Wilhite original drawing published in Pete's book that was in error on a couple of geometry dimensions.

Tom V.

[tom s]

The "early bellhousing is the rub!They weigh a ton and not sure if SFI bells are avail in the aftermarket?IMO the juice aint worth the squeeze!Tom

[hurryinhoosier62]

Originally Posted by tom s

The "early bellhousing is the rub!They weigh a ton and not sure if SFI bells are avail in the aftermarket?IMO the juice aint worth the squeeze!Tom

I hadn't thought of that. Thanks, Tom.

[tom s]

McLeod does not even show a Pontiac bell now and Lakewood and QuickTime only show 64 and newer bells.They don't even show 61-63 I guess because of the bell mounted starter.Tom

[Jack Gifford]

Bellhousing for early block isn't a deal-breaker. I use a Lakewood (which is basically round), drill it to fit the block, and machine a block-saver plate to mount whatever starter I choose.

[Tom Vaught]

Obviously Steve B out west with his Pontiac Dragster had to come up with a certified bell-housing for his efforts, too.

Tom V.

[taff2]

Are we talking manual transmissions if you are on about using the stock early cast iron bellhousing? Surely a manual trans that fits the back of a late Pontiac block will bolt right up to the adapter plate as the bellhousing bolt holes will be in the same locations as they are on a TH400 etc? 1/4" adapter bolts to back of the early block, transmission bolts to the adapter plate.

[tom s]

Jack and all!He is road racing!He needs to get the weight off the front end as much as possible.I see no advantage in using the pre 64 block from a labor or money output.For sure the best deal is a aftermarket alu block.Jack,you have your own machine shop as well as Steve.For the average builder much like me those are not options in my mind.Im doing a swap in my first gen bird to do the same thing but not for competition.Carry on.Tom

[Don Keefe]

Some random notes on the subject:

When we "rediscovered" the Gray Ghost back in 1995, it was sitting in a trailer in Glens Falls, NY with a 303 that used a 366 dry sump NASCAR block and a 2.8-inch stroke Moldex crank. There was also a spare crank in the trailer with the same dimensions.

Herb Adams initially built a 303 using a 326 block and shorter-stroke crank of some sort (details are sketchy). It appears that the engine was put together on a budget and probably used a cast crank with ground journals. That engine blew up at Waterford Hills and after that they used 400 blocks with 3-inch main 2.84-inch stroke Moldex cranks. The rod length was chosen in order to make use of off-the-shelf 400 pistons.

I also believe that the short deck height was chosen at 9.225 inches to allow the use of pistons with the same compression height as a 428 and a 6.08-inch rod. The 7.08-inch rod also allows the use of a 455 compression-height piston in a standard-deck 366 application.

It is great to hear that my old 303 Titus engine is being reunited with the original car. Both had TG-003 designations. It was always my intention for that to happen.

As far as blocks to use, I personally think that the 301T block is the way to go for an under 305 cubic-inch build. The block has a higher nickel content and is thicker than the flimsy original version of the 301 used from 1977-79. Several sources have confirmed the blocks are comparable in strength to SBC designs and Tom Schlauch can confirm that builder Joe Sherman had no issues with the block in his 475-horse 301 stroker engine build from a few years ago. The bore size is right on, so is the rod length and a billet crank can be machined to take into account the slightly different thrust width. Stroke length can run between 2.94 and 3 inches to make the displacement cutoff. Aside from the use of a 326 crank, I think Tom's build is great model for a road racer build. The #15 heads, SD performance CNC porting and slightly larger valves made for a great complement to the relatively small bore. Speaking of SD Performance, perhaps Dave could build a Mega Brace for the short deck engine, which is a little different. As for an intake, Titus used cut-down Ram Air IV castings, which offered a pretty straight shot and I think that approach would be optimal. The two-plane would offer a little more low-end out of the corners but is large enough overall to keep HP numbers up on the top end. I would look hard at Quadrajets in this application for the same reasons.

Here is a gift for anyone building an under 5-liter Pontiac engine for road racing: After extensive computer modeling done when I was going to build my old Titus engine in the 1990s, we were able to figure out why the 303 didn't make as much power as the Fords and Chevys. Taking the dyno sheets from the last 303 Pontiac Tom Nell built, we could see that it made far less power than the cylinder head flow data would support. The engine was making 460-470 horsepower and the heads would have supported upwards of 600 horsepower. What was happening?

The reason was that combustion chamber was too large relative to its total cylinder volume. It's not a problem in a 400 or 455, which has much more total swept volume relative to the chamber size. In order to compensate for that, the pistons had unusually large domes to get the compression up to 12-12.5:1. As we know from the old H-O Racing engine book, you will hard-pressed to get any more than 9.4:1 in a 303 with a flat-top piston and any of the available combustion chambers.

From my 1995 PE article on the Gray Ghost:
General Kinetics also manufactured the solid-lifter camshaft, which featured 300/310 degrees of duration (advertised), 0.500-inch lift, and 105-degree lobe centerlines. In a recent phone interview, Tom Nell mentioned that the maximum lift had to be kept relatively low. “In order to keep the compression up, we had to use fairly large piston domes,” he said. “That prevented us from using more than half an inch of lift, due to piston-to-valve clearance.”

By simulating a compression drop back down to 9:1 and upping the total lift, to .575, the combination picked up a full 100 horsepower. Now that is a simulation but the dramatic jump clearly illustrates that we were on the right path. I think that move would greatly improve the 303's output regardless of deck height. Plus, reduced compression would help with head gasket longevity, a big problem with the Gray Ghost, as well as overall engine longevity.

Discuss?

[tom s]

Don,the 303 std deck engine being built now is using a set of heads and crank from Tom Nell.Tom is helping him with the oiling which will be done thru the stock dry sump system with help from Ken.I found the guy a 366 block and sold him my 366 NASCAR cam which Jim Robertson thinks will be a good start.I hope Jim gets the job of doing the top end.Back to the original OP.Tom

[cabhop]

Originally Posted by Don Keefe

Some random notes on the subject:


As far as blocks to use, I personally think that the 301T block is the way to go for an under 305 cubic-inch build. The block has a higher nickel content and is thicker than the flimsy original version of the 301 used from 1977-79. Several sources have confirmed the blocks are comparable in strength to SBC

Time for a 3" billet crank group purchase...

[taff2]

So, don't spend a $100 on an adapter and a $1000 in machine work, but spend $4500 on an ali block!

[tom s]

he has a block!No need to get a early block!He is not building a top fueler,If he goes to a really big cam he will need a mega brace on either,if he think its needed 4 bolts will be the same on either.At 1 1/2 HP per ci a stock bloc will be fine.I just see no need for a pre 64 block for his needs.If he wanted to go off the edge than a alu block or a short deck would save him the weight off the front end.The early block wont do that.And if he wanted to go to a 4in bore the sleeve deal will be stupid expensive with either block.For a 303 he would be taking a knife to a gun fight with a std deck block.A 301T block would be good for a 303 but it then needs a custom crank and custom head gasket along with 4 bolt caps.My hat is off to him for what he has been doing.Looks like his best bang for the buck is to go the 400 plus route.I like going off the reservation as much a virtually anyone except maybe Jack but a early block has no use in the conversation IMO.Carry on.Tom