What are the limits of a stock 5.0 block N/A. No nitrous no boost just N/A high rpm like 8500+. Will a stock block handle the stress or will it just split in half? I'm trying to figure out my budget for a new motor for my 1995 cobra and i was looking into the new boss block but I'm still on a budget and $1700 is a lot of money.
Stock 5.0 block limits
- Thread starter 94stroker
- Start date
The typical rule of thumb is around 450-500 horsepower for a stock block, but that can still be pushing it. If you're planning on 8500 RPM, you definitely need that thing balanced. I'd get it as close to a zero imbalance as possible. My next engine, regardless of power output will be built on an aftermarket block, simply for peace of mind. I'm thinking I may go 351 based though, so I could probably get away with a stock block in that case, since they can handle more power than the 5.0 blocks can.
I'd be more concerned about the valvetrain handling the RPM than I would the block handling the power. The Boss block is supposed to be able to handle quite a bit (definitely over 500), but I haven't read anything official that states its maximum recommended power yet. For $200 more, you can get a Dart block and know it'll handle the power. Either one is going to need machining, but for the money spent, I'd much rather spend it once on a block that's proven to handle the power.
8500+ rpm is a NO GO with a stock block. I would not trust that at the stock power level and balance.
As for camshafts, good luck getting a hydraulic roller to be stable at that rpm
The Boss and Dart blocks are very comparable in power capability. I would choose the Dart at this point and time though.
Typically a stock rotating assembly can outlast the block. So a "built" bottomend is only as tough as the block itself.
As for camshafts, good luck getting a hydraulic roller to be stable at that rpm
The Boss and Dart blocks are very comparable in power capability. I would choose the Dart at this point and time though.
Typically a stock rotating assembly can outlast the block. So a "built" bottomend is only as tough as the block itself.
Don 95Vert
Founding Member
The stock EEC is about all done at a little less than 7000 - just too many processes to control, you end up losing spark and fuel control because the processor is too slow. You'd more than likely need something like an AEM as well besides what others have already mentioned.
zenboy99
Founding Member
There are a few guys that I know of in the NMRA Pure Street class making over 400rwhp in a NA 306 revving over 7000rpm. But those cars are strickly drag cars so they don't see alot of miles.
Sorry if I hijack the thread, but how does the block strength of the Dart compare to the Boss block?
Sorry if I hijack the thread, but how does the block strength of the Dart compare to the Boss block?
