Going to be building a 400 4 bolt main block from a car being gifted to me in the near future and trying to find a way to get this thing whipped into shape so I can drop it in my '86 Camaro. Going get the block mag'd and bored 30 over and whatever else machining needs to be done. Going to be going back with rebuilt stock top-end for the sake of keeping the initial cost of this rebuild as cheap as possible and upgrade the top-end later on as budget allows. For the bottom end my question is how durable are the stock parts? The car is just going to be for cruising and occasional trips to the drag strip, though I do eventually want to run about 125-150shot of nitrous. If I need to upgrade the crank will this Eagle cast crank be sufficient http://www.summitracing.com/parts/ESP-104003750/ ? Do I need to go with forged rods? Planning on using this rebuild kit http://www.summitracing.com/parts/FEM-MHP139-311/ . Looking to rebuild with a mild cam...any suggestions?

 

Even the stock shortie rods are pretty durable if you don't over-rev them (ditto the crank). They can take a lot of torque, but high RPMs kill them. Invest in good rod bolts and have the big-end machined round again. That's about all you need in the way of "trick parts". Since you're ditching the stock pistons when you do the overbore, get something with a little less dish to it. 12cc dished pistons with stock 76cc heads will put you roughly in the mid 9s for compression.

I ran a 400, like I described above, in my old 79 'Bu for years and years putting tens of thousands of miles on it. It had half-decent heads (old Dart Iron Eagles) and a little tiny "RV" cam (Crane Energizer 266). Intake was an old Weiand dual plane topped with a home-tweaked QJet, exhaust was shorties headers and crush-bent duals. The distributor was just a junkyard HEI with the advance recurved for a performance application. It would go bottom 13s on slippery street tires with a stock converter and 2.73 rear gears without ever revving it over 5800. And I towed my boat with it every other weekend.

After I pulled it out it was rebuilt a second time to go in my brother's 87 GTA with Trick Flow heads, a smidge more cam and a TPIS Miniram intake. Bottom end was still stock crank and shortie rods, just different pistons. It would run high 12s on street tires at 113 MPH, still not shifting over 6000. He drove it almost daily and raced it for another 5 years, once running dead-even with a ZR1 Corvette from a highway roll up to 140 MPH! One quick monkey given the modest budget.

Cam choice... A cheap Summit house brand K1103 cam kit ($90 including lifters) will work well with stock heads and give you plenty of torque through the mid range up to about 5000. Then it'll nose over pretty quick. (Better heads are really needed to get any high RPM power potential out of a big cube 400, so don't cam it to work in any range higher than that).

 

if your planing to use NOS id upgrade the pistons and go to 5.7 rod as for the crank if you have it turned with a large fillet radi it should hold up fine. anything more than 400 hp and Id upgrade the crank to a steel one like you have listed.

 

That's an awesome sounding motor Damon. Making that kind of power reliably with a budget is perfect if you ask me.

What volume were those TFS heads if you can recall?

 

Damon that sounds like exactly what I'm looking for out of this motor. A mid to low 13 second ET on a stock bottom end cheapie build works for me. And upgrading later on as cash allows is the plan. Is there anything in particular I should do with the stock heads? I'm sure I'm gonna have to learn how to do a port job, anything else? Thanks for the feedback guys.

 

The heads will depend on your budget IMO. GM Vortec will work good for a 5k RPM peak but to get the most out of the block you want bigger runners. Hopefully Damon can give advice, it's always best to get it from the guy who did it.

If 180cc aftermarket Vortec heads are in the budget (they run around $800) the potential is there to make over 400hp under 6000RPM.

Porting heads isn't as cheap as people think it is. If you got the patients and dexterity to learn and apply what you learn you can cut out some really nice heads. But the cost is border-lining aftermarket heads when it's all done. Having just finished a set a friend asked me what I spent all together, all tools and hardware, and I figured I spent over $600. Now some of that was bought years ago (tools, grinder, carbies, ect) and some would have to be spent on any used head but that is the cost if you go from "scratch".

The good news though is that you can spread that cost out over a good period of time and the biggest expense is the machine work.