88' Chevy 350 260HP, roller lifters or flat?

[Fordiesel69]

Would the 88 model year be roller or flat lifters? Someone said it could be either unless I pull them and look. Is there an easier way?

I was told by a car mechanic that when GM went to the ribbed valve covers with the bolts in the center, they made the switch. He was not sure with boats.

 

[Pete104]

Re: 88' Chevy 350 260HP, roller lifters or flat?

Have you got serial number?
I just repowered an 89 350 mag, cast iron lowrise intake & the lifters were flat. The number was OD63????
Pulling the intake would tell ya too.

 

[picklenjim]

Re: 88' Chevy 350 260HP, roller lifters or flat?

True the 350 did come both ways in '88 but I would think the 260 hp would have been flats.

 

[wca_tim]

Re: 88' Chevy 350 260HP, roller lifters or flat?

ditto... flat it VERY likely is.

 

[John_S]

Re: 88' Chevy 350 260HP, roller lifters or flat?

While chevy may have converted then, Mercruser phased it in over time. The 350 magnums were first and that I think started to happen '89-90, and the 5.7L 2 barrells didn't see rollers until '97. My '96 and 1/2, mfg motor, didn't have rollers.

Merc's help desk can tell you from the engine serial number.

 

[Fordiesel69]

Re: 88' Chevy 350 260HP, roller lifters or flat?

Is there any major benefit to roller lifters?

 

[John_S]

Re: 88' Chevy 350 260HP, roller lifters or flat?

Is there any major benefit to roller lifters?

Mainly reduced wear at start-up, on these stock and near-stock engines.

During the transition years, engines with flat or rollers were rated the same hp.

To convert to roller, requires new lifters, lifter guides, push rods, fuel pump rod, spyder retainer, roller cam, timing gear, distributer gear, and cam retainer. Can be costly if buying new parts. Some aftermarket kits may provide slight savings over GM parts.

 

[Fordiesel69]

Re: 88' Chevy 350 260HP, roller lifters or flat?

Reason I ask is there is a real concern in the diesel industry with older engines that have flat lifters wearing out because the catalytic converter friendy oils today. If running a roller cam, 350's can take literally any oil. With flat tappet, there are certain oils that will offer greater protection. That is my main basis of concern.

 

[John_S]

Re: 88' Chevy 350 260HP, roller lifters or flat?

I think there are allot of "oil" threads you can read through. Myself, haven't seen all the flat based cams wiping out, or threads from people that had issues, etc.

 

[Fordiesel69]

Re: 88' Chevy 350 260HP, roller lifters or flat?

I havent either, but I have witnessed many automotive GM 350 engines with worn out cams that were gutless POS. Just a new cam & lifters made the engines run like new. My friend used another flat lifter cam when his was shot. These trucks were not over 100k miles.

Not sure if the engine temp in a boat allows it to last longer.

 

[Pete104]

Re: 88' Chevy 350 260HP, roller lifters or flat?

Lucas, engine oil additive! Zinc, makes oil stick to metal. Any oil that has "zinc", valvoline has a racing multi-grade. Purple power has it.

I've been jumpin' up & down about this. I go to Auto Zone, they every Lucas product there is. I ask about the "break-in additive", never heard of it. Advance Auto, they have 6 deep with all other Lucas.

Lucas.com

 

[Pete104]

Re: 88' Chevy 350 260HP, roller lifters or flat?

Answer to question. Roller rockers are now Vortec in a stock app. Previously, it was mild hi-perf.

 

[dan t.]

Re: 88' Chevy 350 260HP, roller lifters or flat?

Roller and flat tappet cams may have been rated the same but reality is a little different. the flat cam is .400 int. .410 ex. The roller is .430 int. .450 ex the lift alone is worth quite a few ponys. Now take into consideration the lobe profile , the roller opens faster, stays wide open 3 times longer, has a tighter lobe center etc. this all adds up to vastly improved volumetric efficiency. Run the numbers on an engine simulator program such as Dyno 2000, the roller is worth at least 30 hp.

 

[John_S]

Re: 88' Chevy 350 260HP, roller lifters or flat?

Roller and flat tappet cams may have been rated the same but reality is a little different. the flat cam is .400 int. .410 ex. The roller is .430 int. .450 ex the lift alone is worth quite a few ponys. Now take into consideration the lobe profile , the roller opens faster, stays wide open 3 times longer, has a tighter lobe center etc. this all adds up to vastly improved volumetric efficiency. Run the numbers on an engine simulator program such as Dyno 2000, the roller is worth at least 30 hp.

The stock mercruiser roller cam has higher lift than the the stock flat but the flat has longer duration. According to merc specs, hp never changed. I've done the change and there is no noticable differance. There are simulators and then there is reality.

A roller cam can have faster ramps. With the low lift that we are talking about here, very neglogible difference. In a car you might notice a very slight improvement in throttle response. In a boat, not going to notice it.

 

[John_S]

Re: 88' Chevy 350 260HP, roller lifters or flat?

Answer to question. Roller rockers are now Vortec in a stock app. Previously, it was mild hi-perf.

The vortec head Merc's (originally called gen+) use the same self-aligning rockers as the standard heads just prior. They are not roller rockers. Just stamped steel.

 

[FreeBeeTony]

Re: 88' Chevy 350 260HP, roller lifters or flat?

I went with the roller so I didn't have to worry about a cam "break-in"....

 

[wca_tim]

Re: 88' Chevy 350 260HP, roller lifters or flat?

ANY engine will benefit from better oil and a high level of zinc - there's nothing else that provides the same level of scuff resistance between iron surfaces (ie bearings too!).

roller vs flat tappet makes a lot more difference when you're going to upgrade / build for horsepower. roller allows for less wear with higher spring pressures, steeper ramp rates which translates into higher lift at the same duration and steeper ramp rates. It's all about area under the curve. In fact something to think about is that the two stock cams mentioned above, roller and flat tappet are not that different. The longer duration of the flattappet is because it has a lot slower ramp rates and so takes a lot more duration to open to similar lifts. even with a significantly shorter reported duration, the stock roller cam probably has about the same or a little more area under the curve than the stock hydraulic cam.