Got a Question. Will big block 6.135 rods be a direct replacement for 348 rods? They are the same length and I was wondering if they could replace a weak area in the 348 without going to an aftermarket rod.
Roy
Roy
Big Block Rods
- Thread starter tripowerguy
- Start date
CDNpontiac409guy
Banned
Roy, with an out-of-the-box 348 piston, the deck height using the factory 6.125" rod, puts the piston .008"-.010" below the deck.
I can see the BBC 6.135" rod bringing it to .000" or slightly above.
Using the .038" - .040" head gasket, this looks like you'd be solving two problems at once
!
You definitely would not be using a stock steel shim head gasket again... but then again, who's making them anymore ?
Not to mention, for the price of new H beams:
http://cgi.ebay.com/ebaymotors/NEW-...ewItemQQcategoryZ33623QQitemZ8033354029QQrdZ1
Why bother with the slightly heavier factory rod, then getting it re-sized, magged, new bolts, ect. ?
I can see the BBC 6.135" rod bringing it to .000" or slightly above.
Using the .038" - .040" head gasket, this looks like you'd be solving two problems at once
! You definitely would not be using a stock steel shim head gasket again... but then again, who's making them anymore ?
Not to mention, for the price of new H beams:
http://cgi.ebay.com/ebaymotors/NEW-...ewItemQQcategoryZ33623QQitemZ8033354029QQrdZ1
Why bother with the slightly heavier factory rod, then getting it re-sized, magged, new bolts, ect. ?
Firepower354
Well Known Member
The Scat/CAT?Eagle I-beams are about $100 cheaper and still plenty strong. If you get the floating version you can amaze yourself for hours trying to slip the locks in without piercing the tips of your fingers. Even the H-beams have came down from the $500+ they were a few years ago.
Thanks for the info Aubrey and firepower. My plan is to put together a new motor with 409 crank (if I can find one) with .040 over 11:1 348 pistons. I know we need to talk privately about this Aubrey but I want to run your pistons. I am putting together the money and hope to start on this summer. I also would like some 340hp heads. Fat says they are worth $350 but I have $400 for some if anyone has some available. I am shooting for 350 to 375 crankshaft HP. If I can't find the heads I will run my own with 2.07 intakes and stock exhaust because I have hardened seats. I plan on keeping my 3X2 carb setup. I have been watching other threads about cams I would like some imput from you Aubrey because the cam I have now is a dog out of the hole, above 3000rpm it comes alive but a Yugo could beat me the first 60 ft.
Roy
Roy
tripowerguy said:I have been watching other threads about cams I would like some imput from you Aubrey because the cam I have now is a dog out of the hole, above 3000rpm it comes alive but a Yugo could beat me the first 60 ft.
What rear gears are you running? A heavey car like ours need some deeper gears to get going.
You are correct though about cams. If you have a mismatched setup like too big a cam for your compression ratio and gearing you will have a dog.
Sounds like your going in the right direction though, build your engine around the cam.
Common mistake, BIG cams with out the right components in enternal parts make a slug of an engine.
Got a freind that would not listen to me on a 350 build up in his Nova and used smog heads, large carb, what he called 9 to one pistons and a big lopey cam.
With the large cc heads I bet he was lucky to have 8 to 1 but it did sound bad a** at an idle !!l
I think he ran a 19 sec 1/4 !!!
,,,dq
DQ I'm running 3.73 rear gears if you remember I bought the 4.11 from you but they wouldn't fit my carrier. I think with the overdrive transmission I can run 4.56 gears and still have a streetable car. The cam I'm running now is a replacement 409hp solid lifter cam from Crane. Every race I have to come from behind to win. Even if I have a better reaction time the other car is ahead of me by the 60ft. light. The only time I ever beat anyone to the 60ft. light was at the HAMB drags against a Dodge Dart with a 273 in it. He had a 4 speed also but it was really slow. The lobe seperation is wide on my cam also 114 degrees and that kills low end. I only bought the cam because I don't have valve relieves on my pistons and the valves get to within .060 to the pistons. I have good double springs on the heads so I'm not worried about vavle float at 6200 rpm. I'm running a BM lockup convertor. Stall speed is supposed to be 2100 but is nearer 1800. I want the lockup feature because it makes the car a real nice freeway flyer. Sorry about rambling on but it's winter time and I'm stuck in the house.
Roy
Roy
CDNpontiac409guy
Banned
Thank you, Roy
...
Here's a cam:
Mechanical,
.595"/.605" gross lift
I'd recommend 1.7 ratio BBC roller rockers. After lash, this cam will give approx. / .568" / .578" lift at the valve.
Advertised duration. 270/274 ( very quick ramp )
Duration @ .050", 240/244
To keep mid range torque at a maximum, grind this on a 108 C/L.
Nasty attitude at an idle.... and break chassis parts over 2000 RPM
Just enough "softness" in the low end, to help prevent flywheeling the tires. If it DOES let go though, it won't come back ( I know this... it's EXACTLY what my Stocker does, even with brand new slicks ).
Would shift around 6000.
4.56's would be a perfect gear set.
... Here's a cam:
Mechanical,
.595"/.605" gross lift
I'd recommend 1.7 ratio BBC roller rockers. After lash, this cam will give approx. / .568" / .578" lift at the valve.
Advertised duration. 270/274 ( very quick ramp )
Duration @ .050", 240/244
To keep mid range torque at a maximum, grind this on a 108 C/L.
Nasty attitude at an idle.... and break chassis parts over 2000 RPM
Just enough "softness" in the low end, to help prevent flywheeling the tires. If it DOES let go though, it won't come back ( I know this... it's EXACTLY what my Stocker does, even with brand new slicks ).
Would shift around 6000.
4.56's would be a perfect gear set.