Motor Mounts

Fred · #1 (**permalink**) 08-06-2002, 10:40 AM

The motor in my cobra is worn out and I am planning on installing either a stroked 302 or a stroked 351W this winter. I noticed a thread in the used parts section about new motor mounts for the CR cobra.

If I stay with the 302 block, I am not concerned with the mounts. If I go stroked 351W block, I will need to lower the motor. Do the new mounts position the motor lower in the car? I have very little clearence now.

I could fabricate new mounts to do this, but if they are already out there, why bother.

Fred

dscott · #2 (**permalink**) 08-06-2002, 11:20 AM

The new mounts from Classic drop the engine 3/4". You can buy the frame mounts from them. The rubber isolators are a NAPA # 602-1639.
Don

Jack21 · #3 (**permalink**) 08-06-2002, 04:39 PM

Fred,

CR didn't have the 3/4" lowered frame mounts yet, so I had to fabricate my own. Used Energy Suspension urethane late Mustang motor & trans mounts. Trans has to be lowered 3/4"-1" also. The engine will move less with the urethane, but car will vibrate more at low RPM. If that's annoying, use rubber parts like Don said.

Think you'll be impressed with 351W or 393W power to the old steed.

Might have to upgrade to Griffin Radiator if you're using old CR brass model. Think I've seen adapters for 302 headers on 351 motors. Don? DV?

Using Edelbrock oval air cleaner. Have seen K&N 9" with filter tops used too. Air cleaner to hood clearance is tight, but it fits. FMS COBRA oval air cleaner that fits with 302, will not fit w/ 351W.

Fred · #4 (**permalink**) 08-07-2002, 07:32 AM

Jack, Don,
Thanks for the info. I will call CR and ask about the mounts. Not really a problem if I have to fabricate other brackets.

I am presently injected and am searching for what EFI manifold is available for the 351. I may end up milling the upper and lower intake to lower the manifold height.

I will use as much as possible from the present engine. I am thinking I will only need a new intake, pushrods, and injectors. My 36 pound injectors may be enough but it is close.

Here is a photo to show how tight everything is.

Fred

Jack21 · #5 (**permalink**) 08-07-2002, 04:31 PM

Option 2. Rebuild what you've got with a 302 stroker (327-347), and if you still need more power, add a supercharger. The FFR guys are way ahead of us on EFI setups. There's a big contingent of FFR types on this forum.

You may want to drop engine 3/4" just to give what you do have some clearance.

Fred · #6 (**permalink**) 08-08-2002, 06:22 AM

Jack,
I am supercharged and intercooled. I am not sure how the supercharger would work with the stroked 351. Probably just drop my boost pressure due to the larger air flow required by the engine. I am going to call the procharger people and ask.

My engine swap may happen sooner than I thought. I may have blown a head gasket last night or something worse. Huge amounts of white smoke (steam?) pouring out of the driver side exhaust. Motor hardly runs. The motor was very tired and I push it to the limit constantly. Hope to have a look at the motor Sunday night.

Fred

dscott · #7 (**permalink**) 08-08-2002, 06:41 AM

I think I would stay with the 302 since everything is already setup. A nice 331 stroker will give lots of power if built properly. I would stay away from the 347, lots of problems with longevity. We just built a 331 for a 95 Boss Mustang it is equipped with a blower . It made 450hp at the wheels. Very fast.
Don

White smoke is definitly antifreeze. Head gasket more than likely.

Jack21 · #8 (**permalink**) 08-08-2002, 03:30 PM

There's a guy here in CACC running a Vorteck blown EFI 302. We figure this engine is putting out what a normally aspirated 460 would, with half the weight. Can break the rears loose without a lot of effort. This is not a "Built" engine either. More like a stock 5.0, with a cam.

A blown 331 with aftermarket rods, forged pistons, Rouch iron heads and a good cam should clean any big blocks clock. The fastest normally aspirated big block Cobra ran 11.2. These blown small blocks are running 9's and 10's in Mustangs. You've already got the expensive stuff in the car already. This "Upgrade" should be a walk in the park. (Until you start breaking trans's and rears)

Fred · #9 (**permalink**) 08-09-2002, 08:01 AM

I have 8.8, disc brake, 5 lug axle, rear end in the garage. Only reason it is not in the cobra is I am not sure what gears I want to install. Waiting until I install a new motor to change gears. Have 3.08's, 3.27's and 3.55's. Currently using 3.55's. I have a lead on a new T-5 tranny. Constantly looking for super deals on parts as I am always breaking something. Luckily I can not put all the power to the ground.

There is no chasis dyno in my area so I use a G-Tech meter to see how engine modifications affect power. Not sure how accurate it is, but at least I know if I gain or lose power with a modification. Last run was 404hp on the G-tech with no nitrous. The bottle is empty. I have the nitrous wired to a pressure switch to help out before the supercharger gets up to speed.

You are correct. I can break the rear end lose at any time. I was along side a Z06 Vette the other day and he wanted to play. Broke the rears loose at 55mph.

I found a stroked 302 short block that will work for me. I should have it in a couple of weeks. If I am not happy with the stroked 302, I will start to gather what I need for a stroked 351

Fred

dscott · #10 (**permalink**) 08-09-2002, 11:07 AM

Fred, Just a suggestion, If you are going to buy a new trans I would spend the few extra dollars and get either the Tremec 3550 or the Tremec TKO. You will need to change the bellhousing also but the Tremec bellhousing is only $135. Well worth the money for the upgrade.
Don

Fred · #11 (**permalink**) 08-13-2002, 08:31 AM

Started dismantling the top end of the motor last night. Spark plugs for #7 and #8 cylinders coated with antifreeze.

Compression checked all cylinders. #7 and #8 are low, about 20 psi below average. So at the least, I probably lost the head gasket seal between these cylinders. #2 is really low, about 70 psi below average. Hope to pull the heads tonight. Something is really wrong on #2.

I may leave the one side alone and hope the motor lasts, especially the #2 cylinder, until the end of the summer season. A new motor is a definite. I would rather do that over the winter.

One question. I see the talk about brake boosters and master cylinders. I am using the stock Mustang II set up. I see 80's vintage vette and some other setup are mentioned. What is recommended? Changing this out would be much simpler when I pull the motor.

Fred