A 305 with mild cam,500 cfm 4 barrel carb,small tube headers and 9-1 compression should make about 250 hp and enough torque at lower speeds to allow a 2000 rpm cruise speed on the highway in lighter vehicles and 20 plus mpg.
To gear for a 2000 RPM cruise you have to decide what size tire you will run. The right gear for a 28" tire will be the wrong one for a 30" tire. At what speed do you actually expect to cruise (any 55 MPH roads in your area, spend any time on them, driving the POSTED limit)? As a fer instance, figgure a 3.42 final, .75 OD W/ a lockup converter (no converter slip, for sake of this example anyway). Tire size in inches V/S RPM @ 55 65 75 28, 1700, 2000, 2300 30, 1590, 1980, 2150 I had to interpolate the 30" #s as the nice round numbers (55, 65, 75) fell in between the incraments on the calc I'm using, but I figure you get my point.
well gee. I'm tickled to get up this morning and see all the replies to my post... I back up here and try to respond to some of them.... I gotta check out the heads today. Looks like the numbers on this one motor show it is a 1980-1984 series. A different motor I have shows it is a 1976. and one shows it is a 1976-1979. If I had a set of heads that were 601. I ***ume I could just bold them on the block I plan on using..?? Or was the block build 'specially' for those heads (some minor changes in some way)..?? Also I do plan on putting an AC unit on the truck. Living near Atlanta and driving it a lot... man, gotta have AC. Yeam.. I'm right with ya here. I been trying to figure out if I will run a 16, 17, or 18" wheel. I'd LIKE to run an 18" wheel so the tire tucked up insid the fender well a little more,.. and also to get the truck a little higher off the ground. unfortunately, The size tire/ wheel combo I am gonne be able to run is going to depend on the amount of front wheel crearance I have. May have to stay with a 16" wheel. ANyway, Back to subject. I had a '93 t-bird and it cruised at 70 mph and was 2000rpm. That what I am shooting for gear wise. It got 25 mpg. It's got a 2.75 gear in it now,.. but I know that'll be too (not sure to call it high or low) in any event it'll be wrong when I put a 700R4 overdrive ****** in it. Finally (for now) someone mentioned flat topped pistons. Where would I be able to see pics so I can see what they look like and compare them to what I have..?? Just curious If I had them..?? Also my piston tops have little smiles (well they upside down) in them and they are in the top 1/3 of the piston. I figured they are either places where they been hitting the the valves or some sort of indicator marks. I'm thinking the pistons should be at the bottom when the valves are open, so the two should never touch. I can't see any marks anywhere on the valves,.. and the piston tops all have the same marks in the same place.
A 305HO L69 motor will have 601 casting heads, flat top pistons for 9:1 true compression, the slightly hotter L69 cam, and 1.84"/1.50" valves. 601 casting heads have 159cc intake ports (unfortunately about 9ccs is a huge divot under the rocker studs) and flow about 200cfm stock with the small valves. The chambers are the smallest of the 305 heads and usually are about 55cc's. With some mild bowl these heads will flow right around 220cfm and fully ported will hit around 240cfm. Just filling in the giant divot under the rocker studs is worth about 10cfm.
I'd call it too tall. Dished, Flat Top and Domed. The 'eyebrows' are called Valve Reliefs, and eyebrows too, since some pistons come with two, and some come with four.
Awright, darn it, I could have sworn you asked about what a flat top piston looks like, now that I read again, I can't find it . Maybe it's early onset sometimers??
yeah.. you right.. I asked.. tops of my pistons don't look like any of these mine just are flat.. two tiny little eyebrows
SO if I understand you right... I'd need to heads to come on the correct b lock. Just putting a 'good' set of heads on any 305 motor won't do me any good. The two need to be a set. Got my fingers crossed I have one. I have three chances...lol
woo hoo... OK.. got to digging and I found out I got 601 heads. in the spot (center of heads) I saw posted where they number "should" be... I have another casting clock (like the one on the side of my clock) In a different place I found 14022601.. so it's '601' heads. Now I see you mention porting the heads. I've always heard anout "ported and pollished" so now I know what they are talking about. Question. Does this help with power or mileage. I'm looking for mileage. If this don't help my mileage,.. no sense in spending the money. I'm just trying to learn, and at $4 a gallon (and rising) all the increases in MPG I can get will pay off in the long run... Also someone mentioned here (or in another thread) about the cam being poor... now that I know I have the 'hot' version of the 305 does this still hols true. Should I toss this cam and get a different one... whats p with it...
I would just clean it up and run it if you want a good reliable milage motor. I am dropping a 305 into my 57' just to be able to drive it around. I have a line on a few of them. Porting will increase both power and milage if done right. With more power the engine will not be working as hard and less throttle can be used.
Yeah, I saw where you said yours have the two eyebrow design. Those pics I posted (except the domed one) are of generic replacement type as I was unable to find pictures of the 2 eybrow kind. The idea being the hole (dish) isn't there in yours so you should have flat tops (ie neither a dish nor a dome).
Those are the 305HO pistons. Other 305 pistons are dished. Later 305's all got those pistons and had a 9.3:1 compression ratio.
305 with a comp 268-h cam, 600 double pumper, junkyard hei and a set of fresh h.o. heads put my 37 damn near into the high twelves(13.0) and i promise it wasnt a junk *** rat rod with the body rusted away. who ever said a 305 is junk is an idiot.
I never understood why Chevy guys seemed to treat the 305 like a step-child as if they couldn't make power with them. Its just a matter of picking the right cam/head/intake/carb/exhaust like any other motor. Ford guys have been making tons of reliable power out of 302 cubes for decades. I guess if you really feel you need that extra 48 cubes to keep up with a 302, so be it. :O
Good grief man, you're in the USA. And you can't find a 350???? If you're having trouble finding a decent 350 over there you'd hate having to live in rip-off England, where we pay double for EVERYTHING rod related that you guys have. If I could pick up the phone to Summit or Jegs or whatever you hot rod supplier of choice is, and have engine parts on my doorstep two days later I'd be in hot rod heaven! Why mess with building a 305 if you want a 350, and you can buy a long motor for next to nothing from a dozen suppliers?
If you think they knock 305 s just mention the 307! Another engine many don't think you can wring anything out of. But just like any other engine, its the combination of parts that make the difference.
My OT '86 Monte Carlo LS stock Lo Po 305 ran its *** off for a stock 305. Dual exhaust with Dynomax Super Turbo mufflers. Pulled the 200-4R and replaced it with a 700 R4 (better first gear and got a vette converter). Changed the 2.41 peg leg to a 3.42 Auburn posi. Modified the computer carb to run richer at full throttle. Removed the clutch fan and used a Z28 electric fan. Put on a Power pulley on the crank only. Stock the car ran about 16.50, the last time I took it to the track with the 305 it ran 15.30 spun the tires through 1st and half way through 2nd. The car had low 14 second potential with traction. Stock 305 everything intake manifold included. They can run good, not great. To rebuild one costs as much as a 350. They are only worth it if you get them cheap enough to off set the loss in power. Marty McF.
Since we have so many 305 experts here, I have a question about my 305 with 416 heads, Mallory ign, Edelbrock and Holly 4brl (not sure yet what model). It really likes 12 degrees advance and high test. sounds like it may have a very mild cam. I didn't build this engine and the builder is long gone, so without tearing it down am trying to get it set up for the best running etc.
How much total timing are you running initial timing really does not matter? There is some power to have in getting the engines timing right.
OK I'm back again tonight... Maybe I can find out some more stuff... THANKS so much to all of you that have chimed in with answers. It is all so informative, and I'm no motor man thats for sure. SO far I found out I got the 305 HO motor,.. and found out today I got the 601 heads. Thats all cool. Highlander said with a DNK serial number it came out of a Camero / Firebird. That makes sense, I'd figure they'd put a HO motor in a sportscar. So now I got a couple different questions... WHat about the cam. DO I need a new one... I know someone mentioned swapping them. If I swap,.. what do I put in. Also was mentioned porting the heads for better mileage and performance. I'm curious what all you folks need I think to do as "upgrades" to improve the motor. Remember it's getting a total rebuild anyway,.. and I am still trying for mileage. In the best possible world, I'd like to get better mileage and performance at the same time. Someone said new headers.... (I had planned on ceramic coated) I think I had mentioned a got a Holley Carb (needs rebuilt.. so I need to find a site that tells me what I got) I also plan on dual exhaust.. separate flows down each side dumped out in front of rear tires Remove clutch fan and installed electric... What about the heads I got.. port then and use them.. or is the better ones to use..?? I WILL have AC, and power steering..... NO EFI or anything electronic. Probably put on MSD ignition. mmmmm.. what else. Throw some stuff at me that gets me to my end goal.
remember when you're going through and building it, the 305 is nearly the same bore:stroke ratio as a 383 (stroked 350...maybe someone didn't know that??). It's pretty common for guys to stroke them out a bit, not a problem but you don't HAVE to stroke it out to make decent power with it. 305 heads are pretty notorious for breathing poorly and are the main reason people stupidly thumb their nose at the 305; even the HO and later EFI heads were not spectacular. get a few quotes on a port job and full rebuild; compare that to the price on picking up some Vortec heads (1996-1999 GM trucks and GMPP 'aftermarket'), those may be the best thing to ever happen to the 305. there are two versions of the Vortec head, one for the 305 and one for the 350. if you want to use a small cam and keep the power in the low rpm range, I'd use the 305 Vortec heads. but if you want to put a relatively healthy cam and maybe a Performer RPM (or comparable range intake) or stroke it out, definitely use the 350 Vortec heads. They have slightly larger valves and flow a bit better.
Put a comp 268 cam in it. With a standard Performer intake, 600 cfm carb of your chioce, and 500 rpm over stall. It will run great and do ok on mileage. My 2cents. Had this combo in a 83 elky for years.
Are you on a budget? Head porting? You can gain flow by porting the heads. I built a bunch of the 601 heads for 350 engines using 1.6 and 1.94 valves. You have to cut the combstion chambers out on the sides or (unshroud) to benefit. Then you will loose compression. They would come out to 64cc after I cut them. Then if you take a .070 angle cut off the head surface you get them back down into the 55cc range. You could gain by just having the bowls cleaned up. Porting will give you power throughout the rpm range without effecting idle quality or fuel milage. You have to work it as a combination. You select a cam that runs to 6000 rpm the heads have to flow enough air to get it there. One more point. You take this to a machine shop and get a engine kit make sure you tell them to get the flattop pistons. Don't just ***ume since it's a ho305 they will order the kit with flattops. They will likely put the dish pistons in because they are more common and cheaper. best way to get the engine parts is in kit form. They will most times order a performance cam with the kit. It's cheaper that way, and you don't end up with 2 cams. Basic stuff here but If you've never built an engine...... Jeff
Thanks.. thats what I need to hear.. basic stuff,.. and ***ume I know nothing. If someexplains something ***ume I don't know anything and start in the middle. It just cuts down on me having questions and having to backtrack. I wonder of I could use the pistons I have. I should of took some pics of them why I had the heads off. They are flat fop and look in pretty good shape. Used a mic on the holes the pictons are in,.. and they seem to be about 'standard' size. look to be slightly smaller at the top due to carbon buildup. Cheet says they are supposed to be 3.76, and I had 3.73 As far as porting the heads.. I only mentioned that because someone else suggested it. SO you think porting them or just new vortec heads would be the best route performance wise. Someone else mentioned bigger valve springs... I forget the context now...
If you buy an intake for the 601 heads and plan to upgrade in the future to the vortec heads you will need to get anouther intake again. They have a different intake flange and take a special intake. The vortec heads rock if you can swing it..... Springs should match the cam. Stock springs will work for small cams. Use caution on the cam. Don't go to big. It's easy to do on a small CID engine. Most cams are rated for a 350. If it has a fair idle in a 350, it will be a little choppy in a 305. Budgit it out. Figgure out what you want to spend and start pricing it out. I used to make quotes every day. If I went over the customers budgit with the estimate I would just ask how much they had, and put together a combo that fell into there budgit. That way they knew what to expect, and I got paid.
If you want to put a cam into it, then do it now. Otherwise, just clean it up and drop it in and drive it. All the other upgrades can be done while you are enjoying it.
I appreciate what you are saying RR. But Just for reference.. I have the truck totally dis***embled now... I want to do everything now,.. and when I put it all back together,.. just be done with it, and do nothing but drive it. To do much of the stuff to the motor I'd have to take the motor out... and to do that (with the Studebaker)... the best I can see I'll have to just about dis***emble the front of the truck to get the motor out. It won't just lift out. To close for clearance,.. and needs to come forward and then up. To do all that I need to take off the radiator,.. to do that I have to take off the fenders, etc.. One piece holds on another. No trying to sound like an ***... I appreciate all the suggestion. Want everyone to keep throwing out ideas. But for all the trouble of removing everything forward of the cab to work on the motor,.. it's easier to fix the motor now, and be done with it. A good suggestion though if I was real short of money. Right now I have been setting money aside to fix the motor so I won't have to fool with it later. I plan on getting it painted to match the body, etc etc.. little chrome here and there. YOu get the idea.
268 cam would be a good choice. I have a 274 in mine and it's pretty lopey at idle but that's what I wanted in the 55.
thanks.. I'm writing all this down, so I'll have items to discuss when I go drop the motor off with my rebuild guy. Just want to make sure I cover all the items, and I know what all to discuss with him. Hoping everyone continues to chime in and I don't miss anything. Thanks to everyone so far.
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