hey, lil new to this but seems like your building an engine for someone else, few things u need to find out from your machine shop,   find out your bore, then your stroke, then check for your compression.  need to know that for what type of gas and spark plug, just need to find out your basic information like valve lift on your cam. iu would suggest after u find out all your info, go to a virtual engine dyno and just play around til u like what u see.still new to this  

well, a 305 can be used as one hell of a big paperweight...seriously, in this day and age you can go grab a 350 in the junkyard for a couple hundred bucks (heck, I have a friend who got one for free!). But it's your money, and if you're hellbent on building some record-setting 305 then by all means, go ahead. Altho this reminds me of a 305 T-bird a friend has at school...we brought out my old beat-up 350/350 '79 camaro pegleg and smoked him...the '79 was burnin oil all the way down the street. W/e.  

What is the specs and brand name of the rv cam I am not that familiar with that cam but it should probably make more torq. than the stock junk cam that g.m. used.With flat top pistons and 58cc heads you should be around 9:1cr witch will up the power a little more as well.  

didn't carcraft do an article on 305 heads on a 350 for the sreet? i think they also did 289 heads on a 351 in the same article. made decent mid-range and low end torque for a street only engine.  

THE BAD THING ABOUT BUILDING A 305 IS ALMOST EVERYTHING IN THE SMALL BLOCK CHEVY WORLD IS FOR A 350-383. YOU CAN NOT-- LET ME SAY THAT AGAIN YOU CAN NOT BUILD A 305 BASED OFF A 350+ CUBIC INCH MOTOR. IF YOU READ THE AD FOR A SBC CAM AND ITS SAYS IT HAS A POWER BAND OF 1500-5000 RPM FOR A 350, AND YOU STICK IT IN A 305 IT WILL MAKE THE CAM "BIGGER". JUST THE OPPOSITE IF YOU PUT THAT SAME CAM IN A 400, IT WILL MAKE THE CAM "SMALLER". 305 HAS A MUCH SMALLER BORE AND TO GET ANY LOW RPM POWER AND TORQUE YOU WILL NEED TO KEEP PORT VELOCITY AS HIGH AS YOU CAN BY RUNNING SMALLER INTAKE RUNNERS. WITH A HEAVY TRUCK AND A "RV" CAM DONT GO OVER 170CC. FOR WHAT YOUR AFTER A SET OF STOCK HEADS WITH MINNOR WORK WILL DO THE JOB. DONT GO CRAZY ON THE HEADS AS UPPER RPM FLOW IS NOT NEEDED WITH A RV CAM TURNNING 4800-5000 USEABLE RPMS. ALSO DONT GET CARRIED AWAY WITH THE COMPRESSION AS A RV CAM DOSENT HAVE THE OVERLAP NEEDED TO BLEED OF CYLINDER PRESSURE. THIS HIGH CYL. PRESSURE A RV CAM PRODUCES CAN CAUSE SPARK KNOCK. IM NOT SAYING IT WILL JUST THAT IT CAN WITH LOW GRADE PUMP GAS AND TO MUCH COMPRESSION. YOU NEED TORQUE TO GET A HEAVY TRUCK UP AND GOING WITH FAIR MPG NOT TOP END HP. SURE 380 HP AT 6500 RPMS FROM A 305 IS GOOD BUT WORTHLESS IN A HEAVY STREET DRIVEN DAILY DRIVER. SHOOT FOR 300-350 FT TORQUE BETWEEN 2000-4000 RPM RANGE AND YOU'LL BE HAPPY. ALSO FLAT TOPS WITH 58CC HEADS SHOULD BE A BIT MORE THAN 9.1 COMP RATIO ON A 305. THATS WHY I SAY TO KEEP AN EAR OPEN FOR SPARK KNOCKEN...  

Maybe I am all wet here but isn't the difference between a 305 and a 350 basically bore and stroke? Couldn't you take a 305 block, bore it to the max, add a different crank, piston, rods, and come up with a 350 or more size engine? I have a 98 Silverado with a 305 Vortec, added an aftermarket cold air intake, and shorty headers, high flow cat, glass pak muffler split into dual exhaust with oversize tips. Which gives it a very nice tone. For what I need the engine has plenty of power. I trailered my 65 Impala home and other than feeling the weight she pulled like nothing was back there for most of the trip. Except for some big hills when she would pull hard but kept at the speed limit. So to me, unless your wanting to go racing that 305 is one great engine.  

impala_65:
Maybe I am all wet here but isn't the difference between a 305 and a 350 basically bore and stroke? Couldn't you take a 305 block, bore it to the max, add a different crank, piston, rods, and come up with a 350 or more size engine? I have a 98 Silverado with a 305 Vortec, added an aftermarket cold air intake, and shorty headers, high flow cat, glass pak muffler split into dual exhaust with oversize tips. Which gives it a very nice tone. For what I need the engine has plenty of power. I trailered my 65 Impala home and other than feeling the weight she pulled like nothing was back there for most of the trip. Except for some big hills when she would pull hard but kept at the speed limit. So to me, unless your wanting to go racing that 305 is one great engine.

There is no difference in stroke.  Its all bore.  It cannot be bored out even close to a 350's.  

one thing u could try is headers if u dont have them. anouther thing u could try is setting the timming to more advanstenced because all of that stuff u put on there  

Uhhhm ok man are you talking about racing wise becaue if you are you might beat a couple of cars but i dont know if a 305 would be the way to go if you wanna race u might wanna switch to a 350 small block or big block and add everything u added2 the 305 and add a  30\30 crank and u should be quick and it would b cheaper 2 fix up if u wanted 2 add anyting else but ya ur engine sounds like u did a really good thing and if u werent talking about racing that would b a great truck 2 hav.  

It's frustrating how quickly this country is losing a grip on the English language...

The above post is a great example of it.  

And sense of timing, the last post was six months ago....  

DOOR STOP...sorry  

DEWD22...add a 30/30 crank?  

Dag on i read this whole article and had a few things to add as i have played with the 305 a bit to with good results but i did not realize the post date on it eather oh well.Hope things worked out for the fellow.  

i have personally built a 400hp all motor 305 that runs great in a 80 malibu with a 4spd, but the same parts would have made maybe 420-430hp in a 350 with better bottom end  

my 305 in my camaro still dusts mustangs. and the 305 in my friends nova is getting great mpgs on a 2 barrel. it's not a bad lil' motor. but don't expect it to move the earth. it ain't bad for a first motor to play on. just don't fork out too much on it for play. just remember you are driving a heavy aerodynamic brick and you are not going to get racing peformance out of a 305, or any motor in that truck. unless you get a big motor that will pass anything but a gas station. play with the 305 for now. and have fun.