Your opinion, 2.7 or 3.0

kent olsen · kent olsen's Garage

I'm looking for some opinions.

To get my 72T to 10:1 pwr/weight, I can build my 200 hp 2.7L up to 230-240HP or purchase a 3.0L and build it up to 230-240HP.

Which would be the better choice? I'm of course looking at expense, reliability (would the 3.0L last longer than the 2.7L) and premium or regular gas.

My car is almost a daily driver, autox and DE's.

Thanks in advance for your opinions.

Kent Olsen
72t upgraded 2.7
soon to be 3.0?

Porsche_monkey · 06-07-2007, 04:28 AM

I think you'll get a better response here if you detail how you would get to those HP numbers with each engine.

kent olsen · kent olsen's Garage

I guess that's part of my question. I have 40mm weber's and headers on my 2.7L, which I could swap to the 3.0L. I've heard that adding them and "S" cams would give 230-240 HP in the 3.0L.

To bring up the 2.7L to that hp sounds like mostly "RS" parts. Pistons/Cyl and "RS" cams which I believe would be at least 10:1 compression. Any more and I'd need to twin plug the engine and then finding and buying a twin plug distributor would be a task. Also that would mean premium fuel and at today's price it gets harder to drive and enjoy the car.

Sooo I'm leaning towards the 3.0L but since I haven't heard many arguments for my 2.7L I'm still open to that option.

Kent Olsen
72t upgraded 2.7
soon to be 3.0 ?

Porsche_monkey · 06-07-2007, 10:42 AM

I believe Wayne's Engine rebuild book details a 2.7 motor that he rates as one of the best engine choices. Have you looked at that? I think it just has cams, carbs, and headers.

I think you can make a fun, responsive engine from your 2.7 at a reasonable cost, but I do not think that your horsepower goal is achievable at low cost with a 2.7.

Porsche_monkey · 06-07-2007, 10:54 AM

If he just timeserts the case he should pretty safe, shouldn't he? That's not super-expensive.

kent olsen · kent olsen's Garage

Well after some more conversations with local engine builders, it looks like the 3.0L is the way to go. More reliability without running a race engine on the street. I can get the HP I'm looking for (230+) with little more than "S" cams, my webers, my headers and Ben's M&K muffler. Plus the weight difference will be minimal with only carbs and headers.

Thanks to everyone who helped with their opinion.

Kent Olsen
72t upgraded 2.7L
soon to be 3.0

911pcars · 06-08-2007, 11:30 PM

Kent,
Plan on changing the pistons/cylinders on the 3.0 if you want to use S cams. The resultant valve lift is not compatible with the domed CIS pistons.

While the budget would escalate by a few thousand, you still might be ahead starting with a 3.0 engine. With the mandatory piston/cam match, one could conceivably go past 3 liters with larger P/Cs. However, that might result in more than your target 230 hp. Sorry about the bad news.

Sherwood

kent olsen · kent olsen's Garage

911pcars

Not bad news, It was one or the other. I was planning on the 9.5:1 JE pistons for the 3.0L anyway.

Now all I need to do is find a 3.0L, put it in my garage and rebuild it. At least I'll still be able to drive the car this summer until it's time to swap the intack, exhaust and hyd chain tensioners.

Kent Olsen
72t upgraded 2.7
soon to be 3.0

kent olsen · kent olsen's Garage

Noah

The 3.0L does have somemore options. As Wayne said you could go to just about any compression with the JE pistons to match your cams. Even 3.2L pistons and cyl is an option. Early 3.0L heads have larger intakes, more top end, or the later smaller heads, more low end torque.

My 2.7L was a rebuild some 10 years ago and I don't know what case work was done but I do know I doesn't have the pistons I was told where in there so chances are the case would need a lot more work as well.

Kent Olsen
72t upgraded 2.7
soon to be 3.0

Lukesportsman · 06-09-2007, 06:20 PM

Just an example: The 3.0 sitting behind my 72 with 2.7MFI RS P&C and E cams dyno'd 230hp.

It is a small port SC and w/ PMO's and 20/21 cams with CIS pistons (KS for that matter) recurved dizzy and SSI's at the time through a M&K muffler. Just a good low mileage core, cams and your parts = your goal.

So even though I love the mystique of a 2.7 MFI reving 7000+, I'm going 3.0 in my 72' too and picking up torque along with about 30 hp.

kent olsen · kent olsen's Garage

The 2.7 that's in the car now, as I said is not quite what I thought it was. It made about 195 HP on the dyno, converted from rwhp (15%). Webers, E cams, and headers but I found out it has CIS pistons. No wonder it never ran right with carbs.

So the path to the 3.0 seems to be the best route. With me doing the work I'll know for sure what is in the motor

By the way what will a 3.0L rev to? I've been using 7000 on my 2.7.
kent Olsen
72t upgraded 2.7
soon to be 3.0

Lukesportsman · 06-10-2007, 05:57 PM

My whimping cam'd 3.0 above peaked at 6000 so I'll likely shift by 6500 or so.

Good springs, rod bolts and other fastners and I wouldn't think 7000 is far fetched with a real cam.

Tom F2 · 12-10-2007, 06:52 AM

Quote:

Originally Posted by Lukesportsman

Just an example: The 3.0 sitting behind my 72 with 2.7MFI RS P&C and E cams dyno'd 230hp.

It is a small port SC and w/ PMO's and 20/21 cams with CIS pistons (KS for that matter) recurved dizzy and SSI's at the time through a M&K muffler. Just a good low mileage core, cams and your parts = your goal.

So even though I love the mystique of a 2.7 MFI reving 7000+, I'm going 3.0 in my 72' too and picking up torque along with about 30 hp.

I'm reviving this thread to ask whether you would, please, tell us what was done to the distributor, and what you are running for venturis and jets in the PMOs.

Also, I wonder whether anyone on the board can say how well the cams, exhaust and recurved distributor setup would work, if the small port CIS were retained.

Thanks.

kent olsen · kent olsen's Garage

tomF2

Now that's an interesting combination. So you have 3.0L heads and case with the 2.7L P&C. I've never heard of that kind of combination.

I was planning on selling all of my 2.7L parts except the hyd chain tensioners, the webers and intakes and the european headers. Then I'd add some cams and J&E pistons with enough compression to get 230+hp while still being able to run regular gas. I would think with the 2.7L pistons you'd have to run premium to get that hp.

Tom F2 · 12-10-2007, 07:52 AM

I think that there's a little misunderstanding, here. The 2.7 in the first post refers to an engine that's in a car, the 3.0 is out the car, but sitting behind it. At least, that's how I took it, because I don't know of any 2.7 cylinders with 3.0 stud spacing.

My question concerns maximizing performance from a small port 3.0 engine, with carbs or with CIS.