so i wasnt exactly sure what motor i had cause i never checked the stroke..just went with the previous owners gumption of a 390...heres a picture of the dowl i inserted in the number 1 and number 4 spark plug holes
the beginning of the first mark is number 1 plug....and just after the 4" mark is the number 4 plug...what does this look like to you experts?
a 360 is 3.50 3 1/2 a 390 is 3.78 3 3/4? thats a neat way of checking it but thats not the recommended way of doing it. once you have the dowel in the number 1 hole roll the motor over to the bottom and remark the stick and then measure. you may have been off a little the way it looks as far as stroke length.
It does appear to be a 390 to me. It's hard to tell though being how the dowl test can be slightly inaccurate. But if you move the measuring tape to the right a little it looks like it would line up with the center of the left black line better... bringing it to just under a 4" stroke.
360- 3.5" stroke
390- 3.75" stroke
well i know its not the original motor cause it came with the 240 and three on the tree....it has part number c4se-9425a
a 64 tbird 4 barrel manifold right? the po said it was from a galaxie.....possible z code '64 390 thunderbird special?
i actually measured it twice and the the measurement is from the beginning of each line( as you look at the picture...its the left side of both marks thats the differnence..sharpy just exaggerates it...came up with about 4 1/8th each time roughly
hate that i used a sharpy but i measured twice for consistancy....it has no casting number on the block to help me out either..just part numbers on the accesaries
Well, I would suggest using one cylinder and a socket on the crank to turn the motor over. Make sure the rod is perpendicular to the face of the piston or it'll measure wrong. Usually you can eyeball the head geasket surface from the front pass side and reference the rod to that so the rod stays perpendicular if you use #5 cylinder. It's also easier to have someone roll the motor over while you hold the rod straight and try to keep it from moving around the piston face.
Maybe you have a 428, maybe you have a 352, who knows without better measurements.
I'll go do the cylinder 1 and 4 test just like you did on my highboy's 390, just to see if i get the same thing as you or if mine shows more like it should (3.75").
head gaskets should be the same or close enough for what we are talking about here. i kind of doubt head gasket thickness or thiness would affect the measurement.
fordman wrote:head gaskets should be the same or close enough for what we are talking about here. i kind of doubt head gasket thickness or thiness would affect the measurement.
I think he is wondering if the complete gasket sets are the same on a 428 as a 352 so he can look at the shape of one or two of the gaskets and determine what the engine is..