I've been thinking real hard about replacing the 2.8 v6 in my DD with a warmed over 350. The 2.8 is absolutely gutless and gets terrible gas mileage for how slow it is(low 18's in the 1/4 mile).

I was thinking about using some moderately ported 416's I've got and something like an XS256. How often would I have to adjust the valves assuming I used proper hardware?

My reasoning for even thinking about a solid cam is that I believe it would return better economy, horsepower, AND low end torque than a similarly sized hydraulic cam.

FYI my 280z came from the factory with solid lifters.

 

Every oil change or so.
How often do you lash the valves on your '77 280Z?

That's a microscopic cam. You can get away with the XS262 i'd think, since it's on a 350, and it'd still be tame.

 

That's doable, that works out to roughly twice a summer. Am I off base with my assumptions about a solid vs hydraulic?

My 280z hasn't run yet so i wouldn't know. It's a completely different design being an OHC engine. I'm still putting the engine together. I just thought it was an interesting tidbit to point out.

 

Yea, that's pretty accurate about a solid cam. You get a wider powerband, so more low end and more top end. Not a life-changingly large difference though, so don't set your hopes too high.

 

Anything's better than the 2.8......

 

For a cam that size, there's no benefit to justify the expense of changing to a solid setup. You'd be best off with a hydraulic roller.
Only when you've pushed the duration of a hydraulic roller to the point where the duration, overlap, and engine rpm are adversely affecting low speed torque, driveability and valvetrain stability, does it make sense to go solid roller.
And if you're thinking solid flat tappet, again there is no benefit for the rpm range you're targeting.

 

Yeah, unless you really like working on your car, it's not really worth the trouble unless you're revving outside the range of hyrdaulic lifters. I love excuses to work on my car, but not everyone has my sickness.

 

if you are looking for a cam anywhere that mild you wont see enough of a boost in power to make it worth the hassle of adjusting lash, especially if itis a DD. if you were shooting for 7000+ RPM, and it wasnt daily driven i could see going solid.

 

I think he's after fuel economy.
So, what do you guys think would be the best V8 combination to get the most miles per gallon?
That's a head-scratcher,huh.

 

That's what I'm trying for...

I bet a vortec headed engine that had the chambers and piston tops ceramic coated with a similar roller cam would do good.

 

My best MPG setup would be:
305 with swirl port heads,
hyper pistons
"peanut" cam
full roller rockers to reduce friction
stock intake with TBI
fuel map in ECM with really lean cruise
195° thermostat
electric cooling fans that are off during cruise

Oh look, I just invented a '92 L03 with roller rockers...

 

Wouldn't a decent exhaust from the headers back give a decent increase in power and mileage? By decent I mean noticeable, not some huge increase.

 

if you want something with good gas milage, a cammed, and built 350 is not the answer.

if you have the cash, maybe an LT1? they are pretty cheap and make decent power near stock and will most likely get better gas milage than the gen one SBC's.

another option would be to build a really mild 350. with your heads a really small cam and tune it perfectly and spray it. it wouldnt necessarily be a beast without the spray, but when you spray it, it would be respectable...

the one question nobody has asked or answered yet, is what are you going to do as far as a fuel system... carbed? TPI?

 

I don't think it would make any difference in highway mileage at all. The engine is only making about 20-25 hp at cruise.
It would make a difference in power at WOT.
EFI would get better mileage than a carb because of closed loop. I think that a TBI would get better mileage than TPI because of better atomization and longer time to mix with air.
Going with a newer (Lxx, better) design would be best, but fudgeing.
It's kinda hard thinking mileage for a change instead of horsepower, huh?

 

I'm thinking I'll run it with a megasquirt 2(I've built a couple) and maybe a used HSR or TPI. I've already got a fresh flat tappet 350 with dished pistons in the basement. I'll probably get a set of shorty headers and a 3" single exhaust.

I've already got a fast car or 2, this one just has to be able to keep up with a minivan at WOT.

An LT1 is a gen 1 sbc with slightly better heads and reverse flow cooling.

It is tough thinking mileage instead of power.

 

Fair enough, I never really thought about it that way. I had just heard that it would breathe easier and hence be more efficient. I guess what they meant was more efficient at making power. I suppose then that dropping in a modern fuelie would be best.

 

i am with you on that one. i am all about power. i dont care what MPG my IROC gets, as long as i can get to the track on one tank... or maybe just one direction. haha.

my stang is the good gas milage. it gets a consistant 15 driven hard. although most wouldnt consider that good.


back to 327???'s posts.

if you can run and tune aftermarket fuel injection well, it would definitely be your best bet, it would't kill the power and would get better MPG's.

 

I'm pretty sure I can make it run 13's and get 20mpg around town Based on the 305 I setup/built for my uncle. It is an L03 with lightly ported 416 heads, ZZ4 cam, performer intake, 350 TBI with 454 injectors, and a megasquirt. Currently the TCC doesn't lock. It runs 14.5 and got 16mpg while tuning(lots of throttle) and making 5-6 passes at the strip. The part throttle AFR's are still a bit rich.

 

it is entirely possible, the rear end gearing and trans is going to have a significant affect on the highway milage.

 

T5 and the factory 3.42 open rear.