choosing my bottom

[DusterBoy15]

i got my top end all thought out but its the bottom end i cant decide on. i read alot and im confused people saying not to go with sealed power or speed pro becasue there heavy and to go with kb, but then i heard that some people have had problems with them because of the top ring gap i believe. and i also dont know what rings to use should i use gapless or should i get regular ones and if i get regular rings can i put them right on or do i have to measure the gap.

for the crank do i go 273 forged, stay with 318 crank or go to a 360 crank 3.58

for rods should i go with the 73 stonger but heavier rods or the 71 rods?

should i zero deck the block?

my goal is about 9.5.1 compression on street gas about 87 or 89
im going to be using 302 heads with 1.75 intake and 1.50 exhaust i think brbracing said to go with.

but please help me out. so much confusion

 

[BJR Racing]

DusterBoy15,
The pistons are the choice of the engine builder, the federal mogul and speed pro pistons are similar in weight and are a stock replacement style, and I would buy the lightest piston that I could if I was going to have to spend the money anyway, as they are similarly priced. The thing with the KB piston is the top ring lan is .080 higher in the piston and thus the need for a larger ring end gap as the ring is closer to the combustion space and will see more heat, so the expansion rate is higher. And yes this is why you have to file fit the rings per the engine bore.
As for the crank the 273 or the 318 will be fine, and the 360 crank is out due to the added stroke and the pistons that you are wanting to use. The KB 167 will get you a 0 deck with the stroke of 3.31 and decking the block. The later 318 rods are 340/360 rods so the weight wont be a issue. And as for the rings the gapless are ment for racing and not for street use and have to have a different bore finish to work properly. Also they wont last as long.

 

[DusterBoy15]

so any later 318 rods or is there a special year?

 

[BJR Racing]

I generally look for the 70's or early 80's engines or rods.

 

[DusterBoy15]

so 71 rods should be good? and up to how much power are they good for?

 

[BJR Racing]

They should be good to 450 or 500 with good bolts and correct sizeing and balanceing.