There were 2 different rods depending on which Boss it was.It was built primarily to qualify the engine for Nascar The Boss 429 had the 4 bolt block was produced only in 1969 &70 had Aluminum 'clipped'hemi heads and came in 2 versions with an o-ringed set of heads and one with a regular gasketed head. All the differences in the blocks were in my first post, other than chamber volume and rocker type there is not a lot of differences in the heads except for the SCJ which had larger ports/valves and requires matching intake.The SCJ ports are so big that one valve cover screw in each head goes right into a port.

They only have round ports (not tunnel ports ,again the 427 FE) although similar to tunnel ports and there were no rectangle port 385 series (429/460 and the 370 truck engine). There was not an overhead cam engine (that was the 427 an FE engine and entirely different, the 429 was designed to replace it/them).

The Thunder Jet IS NOT a performance engine, it is the base line 429 engine nothing special no High performance anything. and when i say higher performance packages im refering to they went up from there but they also went back down to a lower level than they were at to start with.if your gona mess with it start off converting the car to a 460+ engine leave the 429 alone, the car's worth more with the orignal engine in its orignal state, and if you hop it up and blow it up you take a lot of value out of the car, if its not the orignal engine already theres no replacement for displacement. the 427 over head cammer is todaly different. it is a very capable engine however they are very expensive to build and are gona need plenty of gears to run, and before i get corrected by a ford guy there is a boss 429 and a proto type overhead camed 429 but those are todally different than what your gonna have in that ole bird. Most of the differences are in the heads and cams a 429 block is a 429 block its the same as a 460 same bore different stroke, thunder jet and such is a performance package and it being a ford product over the years its changed a few things about 4 million times, so unless your really good with fords or know someone that is best leave it alone its already in one of its higher performance levels.

68 ford thunderbird