(from Jet Thrust news)

"There are many misconceptions about the components of an Avanti engine. Many people think that every part of those engines were a special high performance part. I think this happens because it is common for the big three to produce special heavy-duty parts for performance engines. They do this because the standard bread and butter engines are engineered (read that cheapened) to be suitable for no more than standard use. This saves them a lot of money. Letís use the venerable Small-block Chevy as an example. An engine in a Caprice will have a thin wall two bolt main block, a cast crank, light duty connecting rods, small port and valve light weight heads, a very conservative cam, and a thin tooth type timing chain on a weak aluminum/nylon sprocket. The special high performance Small-block will typically have a thicker high nickel four bolt main block, forged crank, stronger forged rods, free-flowing large valve heads, performance cam, double row roller timing chain, and a few other special items. This also holds true for Ford and Chrysler. Studebaker did not have the financial resources to produce the variety of parts required in order to make their engines application specific. Given the quantity of units produced, it might not have been cost effective anyhow. Consequently, they engineered their engines for worst case scenarios and light duty applications resulted in gross over design. Some heavy-duty parts were added as the need arose just as a few special performance parts were manufactured as needed. All Studebaker V8ís have a forged crank, a thick high nickel block, and adequate connecting rods.

This brings us back to the Avanti engine. By 1962, the big three were producing 400 plus cubic inch engines. Studebaker needed a performance engine for their new Avanti that would compete with the big three but could not spend much money on it. According to Otis Romine, work on hopping up the existing engine was already underway when Andy Granatelli showed up with a supercharger in hand hoping to sell it to Studebaker. I donít know who is responsible for the final product but I believe they combined information learned from the Holman and Moody compact stock car 59 Lark project with input from Andy. They simply hot-rodded the standard production engine knowing it was plenty strong enough to withstand this type of use. This article will examine what was done to make more power. It is surprising how many of the components came right from the parts bins. Some of these are easy to spot by nature of their early part numbers. What follows is a rundown of the engine parts and where they came from.

Block Initial high RPM testing revealed an oil drain back problem. It seems the window in the valley was too small and in the wrong place for oil to drain properly. Revising the casting solved that problem. Along with that, a host of other changes were made to update the block. A full-flow oil filter was added, drain holes for the heads were enlarged, and the freeze or core plug holes were bored through for use with industry standard cup plugs. These changes were put into production in mid 1962 for the entire V8 engine line. Thatís right, the only difference between a full-flow 259 and an R2 block is the ID number stamped ahead of the valley cover. The parts book shows a separate number for an R1/R2 block only because all blocks were supplied fitted with pistons. The Avanti pistons are different than standard 289 production items, as are the 259 pistons. The bare blocks are the same.

Pistons The intended use of the Avanti engines necessitated a new piston. That was also an item that could be redesigned and manufactured cheaply. The standard piston used 1950 technology for its design. The new R1/R2 piston was made with then current industry standard design. It is a flattop piston made with a high strength cast aluminum material and has a non-full, slipper style skirt. It is lighter and stronger than the standard piston plus has less operating friction. It also raised compression.

Connecting Rods These are used as is from the standard production engine.

Crankshaft This also was used as is from the standard engine. The 289 crank did change in mid 62 at the same time the block did. The length of the snout on the front changed slightly and possibly a minor balance value change. If you use an older crank in your Jet Thrust engine, check the snout length in assembly with the vibration damper so you donít bottom the bolt on the crank and get the rotating assembly balanced. The tri-metal bearings used in Avanti engines were actually put into use in all engines beginning in 1961.

Vibration damper This is an R engine only part. With increases in power you get increases in crankshaft deflection. The new damper better canceled that deflection. Evidently the engineers felt that the saucer type damper was at its limit in a standard engine. The damper on a Jet Thrust Lark or Hawk is the same basic part as on an Avanti with a V-belt groove cut into the inertia ring for driving the water pump and alternator. The timing cover also changed slightly with the damper. A degreed timing plate replaced the single pointer.

Camshaft This is another item that was produced specifically for the Avanti engine. The camshaft is the heart of a performance engine and it is relatively inexpensive to alter the profile of the lobe. The R1/R2 camshaft (1557663) is conservative by performance standards but it was a dramatic improvement over the standard cam. To this day, it is a very good street performance cam for any Studebaker V8.

Timing gear The aluminum timing gear (1685777) actually was a heavy duty part used on police, taxi, and truck applications starting in 1961. There was also one produced for six cylinder applications.

Cylinder heads R1 (1557571) and R2 (1557580) heads were new for 1963 part numbers but were used on all engines. The difference between these two heads is the combustion chamber size. They gave an R1/R2 engine 10.25 or 9.0 to 1 compression respectively. On a dished piston 289, those figures dropped a point and a half. The ports are the same as the 1955 and later heads.

Valve train The valve springs on a standard V8 will only control valve movement to about 5000 RPM with the stock cam. With the more aggressive profile of the Avanti cam, a stronger spring was needed. The spring that was used is about 25% stronger than the standard one. It allows the engine to spin up over 6000 RPM before valve float will occur. That spring (188645) came right from the parts bin. It was used on the President Eight. The intake valve (683876) is a standard production item dating back to 1955. The exhaust valve (683875) also dates back to 55 but it is only used in heavy-duty applications. It is made of better material than the standard part so it can better tolerate heat. The rest of the hardware (i.e. Pushrods, rocker arms, and tappets) are standard production items.

Ignition Prestolite was already building a high performance, dual point, counter clockwise rotation distributor for Chrysler. It was easy for them to put these internals in a Studebaker housing. This was supplied in all Jet Thrust engines.

Intake manifold and carburetor 1962 was the end of the line for the WCFB Carter four barrel. The current AFB was replacing it for all the customers Carter supplied. Studebaker was one of those. This required a revision of the carburetor pad on the current manifold casting and it was used on the entire line from 1963 to the end. There are two versions of that basic part. 1557843 is used on all the standard engines and the R2. It can be identified by the two small slots below the carb between the left and right chamber of the intake. 1557472 is the same manifold without those two slots.

All four-barrel engines used an AFB from 63 on. The standard engine used a small CFM sized version but I donít recall what size it was. The R1 used one that flows about 500 CFM. The R2 uses a special built sealed unit with foam filled floats.

Miscellaneous The valley cover on an R series engine is different from the rest by the fact that the breather hole was eliminated. The crankcase is ventilated through a tube added to the side of the oil pan. That was also an R series only item. The other addition was a windage tray added to the oil pan. There were a few other alterations to accommodate the supercharger or other external equipment.

As you can see, the vast majority of these engines are nothing special. The standard Studebaker V8 was a good engine to begin with. There is no such thing as an Avanti block, head or crank as there would be with a Corvette. A few years ago, a friend from Chicago needed a block for his 63 R1 Avanti. He called asking me if he should buy a used one from another Avanti for $400 or a late 259 block for $50. I told him they are both the same, buy the cheaper one, and to save the damaged original so he had evidence of the correct serial number. If the casting numbers were close enough, he could have restamped his number in the replacement block. Service blocks were not stamped so the installer could transfer the original number. None of that was important to this person and the 259 block worked fine.

Andy Beckman compiled this list of the first use of JT engine parts

Part # 683875 683876 Valve first use 1955 259 E28 and heavier trucks.

188645 Valve springs Commander six and the President eight from 1936 on

1545072 Head gasket 1958 V8's with 8:1 head

1685777 Timing gear 1956 heavy duty equipment