Inliners International Forums General Discussion Blown and Injected Guide me...

I'm looking at an engine to buy. A 292 that was used for drag racing. It has domed aluminum pistons (no good for boost) and some pretty serious aluminum rods!
I'm wondering if the rods would be suitable for turbo application or if forged are necessary.
Thoughts?

You need to define your goals a little more. An engine producing 400 HP has much different needs and components than one making 600 HP. Aluminum rods require a lot more attention and different engine building procedures than steel rods do, and aluminum rods are often not required or needed in anything other than just all out extreme HP and RPM situations where steel rods cannot survive. Aluminum rods also have a life expectancy, and since you can't tell by looking at them how many passes or time has been put on them, buying them or using them used is a big risk. Having assembled many aluminum rod race engines, they wouldn't necessarily be my first choice unless the engine requirements wouldn't let steel rods be the first choice.

Absolutely correct!!

Need more input.

Sorry, guys! I didn't think it would make that much difference... figured they would be ok or not.

I would be building this engine to take 20psi. O-ring the block. The actual HP number is of no consequence. If the research is correct, 20psi out of a moderate 292 should be in the 800HP range. In a 65 Nova, that's ludicrous! Not a race car. But will be raced.

Perhaps with a 12 Port head, but not a siamese head. Engine prep again is key, and the required needs and absolutes for an engine at the 800 HP level is greatly multiplied from even the 600 HP level. Its hard to image having several thousand dollars in machine work alone done to an engine, but its often necessary to have one survive at that power level, especially if you only think boring, o-ringing and align honing are all you can do to one. There is a whole other universe out there machine work wise beyond the 450-500 HP level that needs to be done, but rarely discussed here because so few have ever been there.

Just curious what you paid for the 292 - if you have bought it.

CNC-dude ~ I've never attempted even 600HP before. I would LOVE guidance on the requirements to achieve even that!
I know I have to do the following...
Align hone
Deck the block
O-ring the block
Lighten the rotating assembly and balance
Harmonic
Enlarge the push rod openings to accept larger rods
Head work - screw in 7/16" studs, oversize valves, port dividers with matching port work, possibly a stud girdle, roller rockers.

I have no concerns with the bottom end... 7 mains should go a long way in helping it out!
But what else do I need to do? I will prep the block (grind the flash off and de-burr everything.

Efi-diy ~ I've not purchased the engine yet, but a deal has been made for $250... the owner is never going to use it and it came as a package deal with another engine he did want.

The main webbing is only adequate for less severe duty applications, but one thing to remember is that you are planning to push over 4 times the HP to this engine than it was engineered for by GM. 600 HP may not sound like much in today's performance market, but anytime you have a HP level of 2 times the cubic inch, you have a serious amount of stress to all the components, and most require a major upgrade even down to the smallest and obscure of parts and also to detail to ensure it will survive. For example, 2 HP per cubic inch for a 350 V8 is 700 HP, and for a 454 is 908 HP. Even though many of those V8 blocks were over-engineered for racing and High Performance use with 4 bolt mains and higher nickel concentrations in the castings, even then, those factory blocks won't live at those power levels for long.

There have already been guys racing these blocks at HP levels not that much higher than what your planning that have already experienced the blocks splitting length-wise front to back between the cylinders due to extreme cylinder loading from high boost levels because these blocks are thin in that area by design. And custom components have been made to help reinforce the block between the cylinders to keep them from self destructing. The main caps will walk in the cap registers in the block and need to be doweled and/or better main caps installed(billet and/or 4 bolt main). Maybe you have seen illustrations in Leo's book if you have one, showing these mods and others, but they have been put into practice for necessity and not for show. A main girdle would also be money well spent along with better main caps. You are basically just trying to keep the engine from self destructing at this power level and beyond. And this is really just scratching the surface. Remember that whole other world of machine work I was mentioning, well you have now arrived!LOL

I would suggest trying to start your build with a Mexican block if you can find one, they are a lot thicker in the cylinders and will be a better platform to begin with. You'll still need to perform all the things to those blocks as well. A fully counterweighted crank is a good idea also. Do you already have a turbo selected for this build? Are you planning to use a carb, or EFI? Lightening the crank is fine, but lightweight components like pistons, wrist pins and rods will not live at these levels of output for long. That is a common mistake that many novice engine builders make when building high output engines such as this. For a street engine that is relatively low power they are fine, but at some point of power output the lightweight parts will fail and you need to go back the other way and get beefier. Any idea what the average Crower or Carillo brand 9000 RPM Winston Cup Super Speedway connecting rod weighs? 830 grams. When you start combining street driving and high HP builds like yours, think NASCAR engine build, not Bracket Drag Racing or life expectancy will suffer drastically.