2.7L HP figures

[kent olsen]

Wayne

Page 112 113 list all the combinations. I'm leaning back and forth between my 2.7L and rebuilding a 3.0L. What HP will the two 2.7L engines develop?

I'm looking for 220-230HP to give me a 10:1 pwr/weight. Maybe I should just rebuild my 2.7L????

Kent Olsen

[pu911]

Kent,
I had a 2.7 w ported heads, S cams, H/C pistons and MFI, made 240 HP, great motor. The 3.0 L have better heads and cases.
Phil

[kent olsen]

Well the 2.7 I'm running in my 72 supposedly has E cams but it was also supposed to have 10:1 wisco pistons but they are only CIS pistons in reallity.

With webers and headers it made about 190-195 corrected HP on the dyno. I'm hoping if I rebuild it with 9.5:1 pistons and an S or modified cam I can come in with 220-230 HP but that seems like a lot of HP with just compression and a cam?

[jluetjen]

For a given HP, a larger engine will have a "fatter" torque curve, which means that you'll have more torque at a given engine speed. You'll also be turning fewer rev's for a given HP. So a 3.0 will generally have more torque across the rev range then a 2.7. Assuming that you build them both to put out about 230 HP, the 3.0 will be making that 230 HP with fewer rev's then 2.7. Not to mention the 3.0 has bigger valves, which will flow better then the 2.7 heads, which means that a given cam will flow more. Not to mention it has a stronger aluminum case. The downside is that a 3.0 weighs a little more.

Both engines will get there. A 2.7 with S cams and 9.5:1 CR is really just a hi-CR 2.7RS assuming that you've got ample intake port capacity. The factory was quoting 210 with a much lower CR, and by most reports from people with similar configurations, 230 is doable. You might even want to check into some more modern cams like GE/DE40's.

The same applies to a 3.0, but as I said, you'll have more torque across the board.

So I guess it comes down to torque versus weight. The 3.0 will be a more flexible, torquey 230 HP. But it will put more weight into the back of the car, and if you don't have a 3.0 already, it will take more weight out of your wallet.

[kent olsen]

That's one of the things I was considering.

I have the 2.7 engine. So to rebuild it I just have to pull it out and pick up some J&E pistons, have the heads worked on, upgrade the cams, upgrade the oil pump, have the case looked into and put it back together with my webers and headers/M&K muffler.

So much for regular gas but the 2.7 will be lighter and I probably wouldn't make very much selling the 2.7 parts anyway.

I think I'm now talking myself into rebuilding the 2.7L. As long as the previous rebuild took care of the case issues I should be ok.

[Steve@Rennsport]

Kent:

If it were me, I would put off a final decision until the case was checked out. Thats usually the dealbreaker due to the amount of expensive machine work needed to properly rehabilitate those things.