Block Choices
- Thread starter 93oh
- Start date
"FMS sohc a bolt on deal"
Not sure what that actually means but I catch your drift.
The Boss 5.0 iron block is a great choice for a "remedial" hp durable street motor that will rack up many thousands of miles. The 3.700" bore leaves little land between the bores which won't react well to big boost.
If your looking to lay down big numbers and are not as concerned with longevity the Teksid or 3V 4.6 block would be a better choice.
If you plan on running pump gas the Boss block is an excellent choice. If your running big boost with race gas or E85 the aluminum block is a better choice.
Not sure what that actually means but I catch your drift.
The Boss 5.0 iron block is a great choice for a "remedial" hp durable street motor that will rack up many thousands of miles. The 3.700" bore leaves little land between the bores which won't react well to big boost.
If your looking to lay down big numbers and are not as concerned with longevity the Teksid or 3V 4.6 block would be a better choice.
If you plan on running pump gas the Boss block is an excellent choice. If your running big boost with race gas or E85 the aluminum block is a better choice.
Aren't all mod motors on the same bore spacing center lines? I know the 5.4 guys run 3.7" bores quite a bit with big boost. Perhaps their blocks are better suited? I'm not sure, never really looked into it.
The limiting factors regarding the engines ability to hold cylinder pressure is the clamping force between the head and the block, the distribution of the clamping force (number and placement of head bolts) and the sealing area (which gets very thin between the bores). That is why John Mihovetz doesn't run 3.700 bore mod motor blocks.
........... but you knew that already
Don't forget the fact that many who are running Boss 5.0 iron blocks have found that they need to increase the torque value on the head studs to keep from blowing gaskets.
26-30 lbs on a 3.700" bore mod motor is risky. CAT600 (Danial) is running 25 lbs and so far has been successful. Mihovetz runs 50 psi on the stock bore 4.6.
I see. Local guy runs 28 psi on a 5.4 motor bored to 3.7" and ran it that way for a while. Suppose your mileage may vary.
No reason to be scared of the Boss block, I run one on my TT setup. There is a recipe for success with these 3.70 blocks and they can reliably take a good amount of boost with the right components (ARP 2000 head studs, head gaskets, etc)
No one said it can't be done, it's just one of those things where you cross your fingers and hope nothing goes wrong. There are a few guys who had gasket problems who just wrote off the boss block and went back to the 4.6. With the Trinity engine they don't recommend anything over 15 psi but I think the linerless block has a lot to do with that. Not that is won't take more but I don't think it will live very long and will be very expensive to repair.
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