Ok before you flame me yes I have searched and read many posts about varrious 305 builds here and yes I know a 305 is not the best base to build off of.
I am soon to build up a 305 anyway. This is not my first engine build I have built many small blocks but only a coupple 305s.
The builds I have done on the past had 2 different goals in mind that were met well with the build I did. Those builds both used stock bottom end, heads(with a little work over), and pistons.

The build I am planning is going to be going with power and ecconomy in mind. The ecconomy part is why I chose the 305 other than the fact that I have two complete and can get more for next to nothing. The car will be used as an occasional daily driver but it's main purpose will be for long highway road trips of 250 to 2,000 miles.

The vehicle will be pre computer and pre emmisions save for a cat, so the engine will be carburated and I can run whatever exhaust I want as long as I use a cat(s).

I will be running a 700r4 with a manual TCC(lock-up) switch, A manual valve body, and a set of 2.56 rear gears with a set of 265/70/15" tires This would put me at 1,200-1,500 rpm @ 60-75mph in overdrive. Still the super low 1st gear of a 700r4 should allow me to have enough off the line for daily driving.

I should note that I would like to do this build as cheaply as possible yet maintain a decent amount of reliability through proper care,clearance, and replacement of every piece of metal that moves aginst another.

Ok down to the questions.
Using the 305 considering the goal of being more efficient for low end torque in the 1,200-2,000 rpm range. Would using a stroker crank help or hurt?

Of course stroking it will increase torque a great deal. I am however wondering if the small bore limitations on valve size due to shrouding of the valves would harm efficiency more than help torque. Also would the longer stroke cause evacuation on the exhaust stroke to be so much less efficient that the 3.48 stroke or would the properly balanced exhaust system combined with the right cam choice be able to take advantage of the increase velocity to make scavenging better?
I plan on keeping oem valve size and doing minimal port work to the heads as I want to mainatin velocity rather than big flow.

Keep in mind also that the crank would be ordered pre machined and the block clearance work would be done by me. The only machine work I would be paying for would be hot tank and magnaflux of the block with new cam bearings installed. Everything else would be done in my shop accept possibly required balance work.

If stroking it turns out to be most efficient there are a few options here also. The cheapest way to stroke it and still use a high lift cam would be to use 400 rods and stock pistons which would just mean external balancing and a bit lower compression. It would also mean less clearance issues. The option of using a 5.7-6.0" rod would add the expense of pistons, restrict cam choice, and require more clearance work.

Just so you know I have allready read many posts on the topic of stroking a 305 for various reasons. Yes I know I could get more power out of a 350 or 383 etc... So up front just to disclaim to those of you who are allready getting ready to say "use a 350 it's cheaper or better" Pulling wheelies and running 12sec 1/4 miles is not the goal in this build. The goal is an efficient cruiser with enough power to get out of it's own way.
I feel the 305 is the best choice to build off for this because of it's ablility to run more efficiently vs a big bore. I would also just love to have an old iron v8 getting better mpg and more power than a 4 banger. I have built up a 305 in the past that got 25mpg HWY with 3.08 gears and would like to improve on that. Think it's possible?

I am not hard set on stroking it but after pouring over power curves using different combinations it seems nothing comes close to the low end torque. I know of many options to increase top end performance of a 305 and have seen a few builds hitting the 400hp mark without stroking.

So what it all boils down to is would I be able to maintain 70mph more efficiently with a good cam, intake, carb, exhaust, and igniton alone? Or would the stroker combined with different cam and intake do better? Or would stock stroke and some 10:1 pistons do better?

PS: Any sugjestions on inexpensive mods to meet the same goal are appreciated.

pps: Yeah I know I am crazy you don't have to tell me

 

If I were you I would just build the 305 with a MILD roller cam, somthing like the L98 cam and forget all about stroking it. But with those salt flat gears I can't help but to say Your going to need a 350 just to keep the thing from having to downshift going up hills and such. I've got the two cars in my sig and drive both on long trips, when I first got the 92 I thought I might keep the 2.73's in it and mainley use it for an interstate cruiser. It does do well but it really needs to be going 80 mph to keep the engine from being under too much of a load. After driving it for a few months ( I just aquired it in april ) and realizing that I still have to drive it in town from time to time I have said TO HELL with these 2.73's. The 87 is a l98 auto with 3.27's and gets 25 mpg on the highway, the 92 is a lb9 auto with 2.73's and the best I've gotten is 23 mpg on the highway. Both cars are in tune so I've come to the conclusion that unless I plan on driving at 80 mph or more on every road trip 3.23's or 3.42's are a better gear overall with a 700r4.

 

Hey thank you for your insight and experience on this.
That bogging and/or down shifting issue you had was why I was trying to build the engine to perform best at that specific rpm range of 1,200-2,000 rpm. To maintain 65mph @ 1,500 rpm on a flat doesn't require much HP but going uphill will so if I can tune the engine to put out good power at low rpm then I should be able to maintian speed in 4th for the most part. With the 2.56 gears though downshifting into 3rd for a 1/4 mile run up a mountian over a 2,000 mile road trip won't really make a huge impact in ecconomy. BTW I do usually avg 80-85mph on road trips but at 16mpg that is getting to cost a bit to much.

 

Your considering a 334, not a 305...but I'm not inclined to answer your stroking the 305 questions.

Consider fuel injection (Properly tuned, the fuel mileage will increase, especially at part throttle), And consider a 6-speed. I wouldn't go lower than the 3.08:1 gear.


This combo got right over 30 mpg...

355
Accel/DFI fuel injection
Edelbrock tunnel ram modified for fuel injection
AFR heads (size ?)
Crane 113801 cam
TRW flat-tops
CR 10.3:1
Stock crank
MSD ignition
6speed
3.08:1 gear

w/ nitrous it did 12.64sec@117.21mph

 

Hmm those number you posted are great smithc.
I am still considering keeping it a 305 but am debating the value of the 334 for low end torque gains.

The point you bring up about fuel injection is a good one. I however am honestly quite ignorant on such systems other than general mantainence.

What would a multiport system run money wise? Would I not need a complete computer engine management system?

 

Do a search for John Millican. He does LT1 intake conversions...about $400 for that IIRC. That doesn't include computer, harness, and sensors you'll need, I think.

A complete TPI type system might run you about $500 I think...including all sensors. If you still needed a wiring harness...Painless Wiring has them.

You'll still need to get on the Prom board and learn how to optimize for fuel mileage.

There are books out and plenty of info on swapping the TPI over to non computer controlled cars. Lots of "Hot Rodders" do this just for the TPI look.

EBAY should be a source of good prices.

The fuel injection is something you could do over time...or just find a 305 TPI and drop it right in, and go to prom burning...shouldn't be more than $1000 for the whole shibang! Unless you change the cam and do headwork.

My 350 car gets about 24mpg on interstate when the lockup is working. My 305 car is all stock down to the air filter. 20 mpg. 3.45 gears, though.

 

Hmm I have read a bit on that now and I think I will shy away for now but possibly do another build over time on a stand to get it right. For now though I will still be rebuilding a carbbed 305 by thanksgiving. That way I can break it in and the 2,000 mile trip for the holliday will give me a good trial for mpg.

I think I might just do a high lift cam and complete rebuild as I can complete that for under $400 total in under 3 weeks.

Heh it sounds so stupid to me now "low end torque monster 305"
But still $400 isn't going to break the bank and it will get me closer to the goal and provide a reliable power plant while I build up something else.