I'm undecided on carbs, downdraft webers or tripower carbs. I have a 65 LT code engine thats not bored out to 425, yet! thats going into a 50 roadmaster rivi & tri power carbs would be way cool looking but I'm not sure if that set up will give me the best performance. Going for the cool 50's custom look on the car. Anybody, Info & advise, pease!!!!ray:
1st. bit of advice, DON'T BORE TO 425!!!!!!! 2nd. bit of advice. Dual Quads WILL out perform trip's any day of the week.
I'll "third" that comment, don't even try to bore a 401 out to 425. Stick with the dual quads, I tri-power is a lot of glitter but a hard tune. Had one on an Olds once, and I spent more time under the hood trying to tune it than driving it.
The 401 and 425 use different blocks. The stock 401 bore is 4.1875, while the stock 425 bore is 4.3125. Usually folks are leary of boring a 401 .060 over, which even then only yields 412ci. Boring a 401 to 425 is asking for trouble, and I'm not even sure it's actually possible.
As far as I know it would make the walls too thin to support the heat and the torque. The walls on the 401 are exactly the size they need to be, and from what I've read here and in other places, (Tom and Doc both know best) one isn't even supposed to go .020 over on a Nail. The 401 and the 425 were made from essentially the same external block casts, but the internals had been changed to reflect the slightly larger bore size of the 425. The water jackets were "shortened" (for lack of a better term) accordingly. I'm sure Tom can comment better about this, and probably will.
Tom I was told that the 401 engine block with a LT code was bilt with thick cyl walls to be bored out to 425 at the factory if they were running short on 425 blocks also this block was cast only for one year when the demand for 425's was high. I hope this person did not blow smoke up my tailpipe about this engine:eek2: Harry
Harry, you take a HUGE risk going over on a 401. It IS NOT an "unbored 425"(although it would seem so huh?):idea2: . I think there is a big core-shift issue involved. YOu might get lucky after getting the block checked, but it is akin to installing hardened seats- if you get lucky, great!ray: But the danger is very real.:shock: I think overheating is a big issue as well. (Don't listen to me though, I just regurgitate what I've learned here:Comp: :beer ). Tom, Doc and a few others are the hands-on geniuses. They will steer ya right!!!!:TU: :Smarty: Welcome aboard dude!!!!:3gears:
Harry, most people don't know what they are talking about. Send me your phone number & I can explain it to you. It would take me hours with one finger. Then if you want you could pass it on. Tom T.
Guys, Thank you for all the information.:TU: Sorry it took so long for me to reply but I was at sea, no internet out there, a real bummer!!!! Tom I'm not comfortable with putting my phone number out there on the net & this system will not allow me to put a email address because my thread count is below 10. If you provide some contact info I'll contact you this weekend or when its convenient for you. Harry
J-Pop, Thanks dude. I to am proud to swim home. My 50 rivi got some katrina water too. Some of the ships I work on are in Violet and the guys down there ended up with ford & gm submarines. Later, Harry
QUOTE: "I was told that the 401 engine block with a LT code" That simply stands for the year and displacement. L= Year: 1965 and T= CID: 401
