Inliners International Forums General Discussion Engines 261, Is It Punched?

I picked up this 62 nova for the kid n me to build, i was told the motor was a 235. the guy said it was a screamer till 1 hydraulic lifter went bad. then while it was sitting in his yard someone stole the offy 2x1 intake n carbs. so i pulled motor, tore it down, first thing that caught my eye were the pistons.(i listed question "261 pistons" last week.)pistons say "jahns" inside. after some research i found it to be a 261. cast #3733813. cam says 272 on end. block very clean, other than the lifter motor seams sound. ive read the bore should be 3 3/4. is that correct. my pistons are 3.865 havent mic. the bore yet. just had a buddy mic. piston while i had it with me. also read some 261's were punched .125 any help/knowledge would be apprec.

I have a 261 block that has been bored to 3.875" for 278 cubic inches; it uses Venolia pistons purchased from Bob Toros in 1961. No problems. Toros used to advertise 3-15/16" pistons for the 261, but I do not know anyone who has used that size. The famous article in the May 1955 issue of HRM about the 261 dyno test by Frank McGurk indicated that McGurk felt that there was no problem with the 0.125" over bore. Has anyone out there had a problem or ever sectioned a block to see how much wall was left? Just how much wall is needed?

Hoyt,

3/16" over pistons were run by Tom Finn in his 50 fleetline at B'ville and El Mirage. He eventually split the block - but we're talking about a full race motor, running at max rpm every time it was run.

I now have these pistons, and intend to run them in a 261 I'm putting together with a cam Tom also gave me.

It'll be a couple of years before I run this combo, so don't hold your breath!!

Tom Langton advised me not to run this combination due to it severly weakening the bores, but due to the historical significance of these parts - I HAVE TO!!!

I intend to fill the block up to the level of the freeze plugs, as an attempt to stablise the core and minimize block flex, and hopefully prevent the cracking of the block.

Mark

Are you sure its a 261? Nova's never came from the factory with a 261 or 235. From the factory in 62 it would be a 194ci. Direct replacments for the 194 is a 230 or 250. It appears from the casting number that's what someone did. If it is a 261 there would be modifications needed to get it in. I also own a 62 Nova. The 230 and 250 has a bore of 3.875 also.

Terry
Novaconv

kind of an odd swap.... a 261 into an early nova. especially when you consider the added weight. hmmm

cast #is 3733813. also has the captains bars. i'm new to these inline 6's. spent the last month researching. according to everything i've found it's a 261.

It sure does sound like a 261. There are obvious physical differences between a 261 and a 250. Someone may have had access to a 261 and thought it would be better than the 194. The 261 is a good engine.

took the block over to buddys shop today...bore is 3.875 the jahns pistons are 3.865 from what i've read the difference can be .005-.011
anyone know if that is correct and where to find a set of rings.