There Comes A Time In Every Mans Life When He Has To Make A Choice And My Choice Right Now Is What Pistons To Use. Here Is What I Have Right Now. Comp Cams 260 And Comp Cams K Kit, Hedman Headers (also Have A Pair Of Efi Manifolds) Mallory Unilite Dist, Mallory Highfire 6a Ignition Box W/ Mallory Promaster Coil, Taylor Wires, Edelbrock 500 Carb And Electric Fuel Pump, Offy C Series Intake, Harland Sharp Roller Rockers On A 240 Head And Others I Cant Even Think Of Right Now. It Is Going In My 1975 F100 Short Bed 2 Wheel Drive W/ 3speed Converted To Floor. My Question Is What Choices Do I Have To Get The Highest Compression Possible To Run Premium With Out Pinging. I Want To Run 300 Pistons, Dont Feel Like Mix And Matching From Other Motors. Dont Mind Paying For Machining On Block Or Head Just Need Some Info As A Starting Point. Just Looking For A Good Combination Of Piston And Machining. Thanks For All The Info You Can Give And All The Years Of Info On This Site I Read Almost Everyday Thanks Again Aaron/oregon

 

the best solution would be to bore your block .050 to accept 390 pistons, the pin diameter and compression height are the same, it worked quite well for me ..and you get two spares in the set PS the 4.050 is a standard bore size for the 390

 

If your willing to spend between 600-700 as set of custom forged from someone like Ross will get you what your looking for.

 

misterfisher what brand did you use on your engine? what do you think your compression is? it seems like something worth looking into probably a little cheaper then custom pistons and like you said you get two more thanks for the information thank you also sr_crewchief

 

Shaft Turner accidently logged in with my account . He'll be online later tonight.

 

There are a wide variety of pistons out there for the 300. Silvolite makes about a dozen of them and some are hypereutectic for more strength. With a 240 head and an early small dish piston you should have plenty of compression.

 

any major manufacturer offers 390 slugs in a variety of styles, mine are just 180 dollar clevites ,as for silvolites they are a flat top but sit the piston about .125 down in the hole.My motor according to my numbers is aproaching 11/1 but wil be running on propane it is also zero decked and has had extensive head milling so just adding the pistons would probably be enough with the big chambers.

 

Silvolite does offer the true flat top HD piston that is designed for 7:1 compression in a stock engine, but they also offer several others with a variety of different dishes. The early pistons have about a 19cc dish that should yeild nearly 10:1 with a 240 head.