|09-24-2011 12:56 PM|
|09-24-2011 01:27 AM|
For a 5200 lb unladen weight truck that will be used as a truck plus pulling a trailer to boot, you need a 454 BBC minimum. Or plan on driving the truck w/your foot in a cramp from trying to push the throttle through the firewall every time you hit a rise in the roadway or a headwind.
If you're determined to use a 350 SBC engine, do what the factory did in those cases- a 4-bolt bottom end w/a forged crank. 4-plus tons of weight to get moving and to slow using engine braking will twist/flex hell out of a crank- cast need not apply. Go the factory one or two better w/better heads like the Vortec truck heads or a similar aftermarket head, long tube headers and free breathing induction and exhaust systems. I'd say to go the 383 stroker or 400 SBC route, but by the time you did that, you could have a crate BBC engine in it that will out-torque either of the SBC engines.
As an example, Demon Engines sells a crate BBC 4-bolt 454 +0.030" (461 ci), Peanut Port heads (118cc chambers = 9.4:1 CR, stock valve sizes) w/a XE 268H Comp cam (.515"/.520" lift, 224/230 @0.050" duration on a 110 LSA). With a Holley HP 750 carb and a (too-large) set of 2.25" headers, it made 446 HP @ 4900 RPM/542 TQ @ 3600 RPM, 490 ft/lbs @ 2500 RPM. Cost $2650 w/no core charge.
|09-19-2011 02:20 PM|
|11echo||I guess I’m going to take the “other” point of view. “IF” you’re building a race machine then I agree with the others here. However “if” your just building a street machine then I’d advocate looking into buying the “old goodies” …I’m just going thru a set of 781 big block heads for my street machine. I had them checked for cracks, decked, bronze guide inserts, hardened seats, teflon valve seals, over sized valves, and stiffer valve springs put in. Plus I when through the heads and de-burred/gasket matched the ports, and polished the chambers myself. Now some folks call that work, I call it fun! Plus the feeling you get when your engine is running real strong and you KNOW every part! …I sure the “Rat Rod” folks know what I’m talking about. …My $0.02, Good Luck!|
|09-19-2011 10:20 AM|
|SloeRyde||I've went through a few sets that looked ok, nope... junk. A few more... also junk. Good luck, hope you find good ones, but prices for new are really getting close to rebuilding used, especially for an average mild or stock build with a common engine like the sbc.|
|09-19-2011 08:14 AM|
You take old heads to any machine shop they are gonna tell you it needs guides. Then you start to spend the cash, once thought saved.
If there is a pile of engines in a section. fresh ones are on top, get there before first snow. Then rotate the crank by hand, it will tell you much.
Find a totaled good truck with air bags deployed, little front intrusion, it is pretty safe.
|09-18-2011 10:06 PM|
I agree on new. ESPECIALLY if you are on a budget. Listen to the wisdom, unless you are very expedienced and pretty savvy on evaluating used parts, you could end up bringing home 2-3 sets before you find some that aren't junk and you will have to pay the machine shop to evaluate them for you.
Also, mu opinion, you don't want the big intake valves on that truck, 1.94 would be plenty because of the rpm range you will normally be driving in.
|09-18-2011 06:42 PM|
|cool rockin daddy||
|09-18-2011 03:47 PM|
Have a deal worked out. Good 906 Vortec heads, GMP v6 springs and retainers should be about 300.
valve sizing, you should half the bore + - a tenth.
Heads are everything. Switching to Vortec heads on GM, and Magnum heads on the old Mopars, is beneficial even to a completely stock bottom. The new technology will bump you ahead. Easily the same GMP series 2 v6 beehive spring and mini retainer, will fit both brands of heads. Ford guys, go do whatever.
|09-18-2011 03:13 PM|
Oops. Sorry about putting this in the wrong forum. Unless I win the lottery, this will probably be a very tight budget build. Therefore my interest in used parts.
Am I correct that not much appreciable power can be made using these heads? Even if anything else was fair game? (Short of forced induction it nitrous)
|09-18-2011 11:37 AM|
2 Words Be Careful!!!!!!!!!!!!!!!!!!!!
Buying engine parts used is a scary business unless you really know what you are doing.
Unless you can check the heads first for cracks and other stuff I don't think I would try it.
I have seen guys buy heads and cranks and other stuff only to end up with someones junk.
I have guy's bring me cams that they bought because someone told them it was a hot cam.
I would profile the cam for them and write down all the numbers checking degrees of crankshaft rotation and duration and center lines, lift and all that stuff.
I would let them watch me do it if they wanted to do and when I was all done they would ask me well what do you think of my cam.
I had to tell them they had bought a piece of crap.
Then I would explain why it would not work right for them or what was wrong with it.
Be careful buying used engine parts and if you are not sure what you are doing try and find someone who will look at the parts for you.
My favorite saying is "In Life people get the right answers to the wrong questions"
|09-18-2011 09:34 AM|
|Hoyt71||Don't have a clue yet. All of my thoughts and research point to 64cc heads vs the 76cc smog heads I have regardless of what my end goal ends up being. It is a 5200# truck with 4spd 3.73 rear a.d stock tires. Right now it will be used as such and possibly pull a trailer some. I'm thinking 5000 rpm max. This is a future project, so things may change.|
|09-18-2011 09:33 AM|
Those RHS's above have 50cc Chambers
The RHS Vortecs are a better choice, better cooling, thicker Decks etc.. over the GM Vortec's.
These are setup for more lift also.
|09-18-2011 08:55 AM|
Buy new aftermarket castings and save yourself the hassle. A swap meet might net you a set of 2.02 heads that look decent, but they might need a valve job, exhaust seats, valve guides, seals, and new springs, so the total price might get up around $500-$600 quite easily. Not to mention you'll have 1960's technology and performance.
Here's a brand new fully assembled iron head that will deliver performance similar to "fuelie" heads: $309.50 each
For a little more here's an iron head that will stomp a "fuleie" head into the ground: $485.00 each
|09-18-2011 08:41 AM|
|T-bucket23||I am also a proponent of Vortecs, just keep in mind they require a different intake manifold.|
|09-18-2011 08:38 AM|
The heads should match the combo. I would buy new. If you buy a set of completely worn out heads you`ll invest $500 or more into them to bring them back into shape. There are some excellant deals out there on new Vortec heads. If you go Vortec I would stay at 1.94.
What is your combo? What`s the goal of your combo? If the combo matches and works together as a team, it`ll make impressive power. When you got a bunch of mismatched parts it don`t work so well or when you try to sneak up the ladder and let one part be the team that don`t work either.
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