Bored R3!

[mfg]

The early 299 CI Studebaker Avanti R3 engines were bored .093 over the standard 289 CI Studebaker V8's cylinder bore size.......True?

[r1lark]

False. The 0.093" overbored 289s were the 304 engines.

Return trivia question -- what did the Granatelli's do  to get 299 cubic inches out of the 289?

[mfg]

8 minutes ago, r1lark said:

False. The 0.093" overbored 289s were the 304 engines.

Return trivia question -- what did the Granatelli's do  to get 299 cubic inches out of the 289?

False is Correct!...as to your question, the owners of 63R-1025 say Andy 'adjusted' the crankshaft stroke to gain the extra cubes, and also to increase low end torque.

[r1lark]

22 minutes ago, mfg said:

False is Correct!...as to your question, the owners of 63R-1025 say Andy 'adjusted' the crankshaft stroke to gain the extra cubes, and also to increase low end torque.

OK, I wasn't sure. I thought it was just less overbore, like 0.060" or so.

[mfg]

You're correct in that a .060 overbore produced the 299 CI....but apparently on at least one engine the stroke was increased slightly to achieve the same 299.

[Geoff]

Yup. In a phone call to my father, Andy G. confirmed a stroke increase from 3 5/8" to 3 3/4" in engine RS1021, and that it was the only stroked R3.

Standard 289 --> 299 practice was to use 0.060" in overbore.

[mfg]

1 hour ago, GeoffC312 said:

Yup. In a phone call to my father, Andy G. confirmed a stroke increase from 3 5/8" to 3 3/4" in engine RS1021, and that it was the only stroked R3.

Standard 289 --> 299 practice was to use 0.060" in overbore.

A very unique Avanti engine indeed!