The 305 is a smog dog. It's not worth building. Factory, they topped out at about 200HP. Strip the free engine to a bare block. Set the block in the front yard. Plant flowers in each cylinder. Now go buy a 350 block and build it.
__________________ '95 TA vert - 383 stroker and lots of miles
I don't know much about them, but i wouldn't waste 5 seconds on one
__________________ 1993 Z28 LT1 T56/M29 1.6 pro-form RRs, Fastchips, 160 t-stat, B&M short shift, Jegs opti, msd coil pack, msd super conductors, TB bypass,airfoil, all emmisions crap gone weighing in at 3100lbs
2000 S10 4.3L/4l60E DD no mods unless it breaks, and homemade CAI
Alright, on a serious note, if it is free and you are determined to use it, the only 305s in my book worth using are the 87 up models as they are roller from the factory. So cam selection would be the same as any SBC for flat tappet, but the factory roller is the plus.
Yes, they handle boost as any other chevy motor, very well.
If you blow it up, you are not out anything, the low compression it has would work great with it i am sure. But it will lack torque, nothing soe more boost not nitrous cannot fix.
As for power, the block can handle 400 HP easily, any more than that and you need block prep work to make it live, not worth wasting money on as you can see by the above comments.
The weight argument it stupid, compare a Warhawk LS motor to a all aluminum BBC, the weight difference is worth it to me with the kazillion more cubes.
running a small positive displacement supercharger, the stock bottom end can survive 500 crank HP if you have NO detonation and keep the rpm reasonable. The most information on 305s is gonna be found hidden all over www.thirdgen.org
The reason everyone bashes this little engine is due to the bore size. At
3.736" you can't get a decent set of heads on there. The stock valves are 1.84/1.50 and that's the "high output" L69 heads. The standard 305's had 1.76/1.46. Even a set of Vortec heads would be severely shrouded and kill flow and subsequently power production. If that's what you've got and you've got money to burn.....go for it, but don't expect it to run with the big dogs! If it were me, I'd spray the ever loving crap out of it until it explodes. It's the least outlay for the most power.....and an awful lot of fun!
__________________ 2001 Z-28....Gone, but not forgotten!
Location: Born/Raised North East, MD Lived in VA, NC, Currently Michigan
Posts: 1,007
your in jersey. ill be up there in a few weeks on a coast guard cutter. id be more then happy to take that off your hands because i think my 92 is on its last leg. hell id even drop you a few bucks for it. im not going to BUILD it just a freshen up to hold a lil longer while i finish my 383 build for my ragtop. and plus an extra motor in the garage to me is an extra motor it can always be just a good motor on the stand "IN CASE"
__________________ ***3 TEXT LINE LIMIT (BLANK LINES COUNT ALSO) WITH PIC IS THE MAX!!! -Admin***
the standard 305 valves in '76-'79 were 1.72"/1.50", thereafter they all had 1.84"/1.50". and even if you have a regular version, a set of vortec heads and a COMP XE268H10, with an RPMAirGap and a set of long-tubes will get you 370 HP at 6100 rpm. Trick Flow makes a set of heads just for 305s.
my little 305 ran good with the vortec heads on it. i used a 1094 head gasket and a 480 lift lunati cam. car weighed 3100lbs with me in it and went 8.0's all day long. stock rockers and eveything. never broke anything. i miss that. by the way whats the bore on a ls1?
my little 305 ran good with the vortec heads on it. i used a 1094 head gasket and a 480 lift lunati cam. car weighed 3100lbs with me in it and went 8.0's all day long. stock rockers and eveything. never broke anything. i miss that. by the way whats the bore on a ls1?
A little better at 3.898".
__________________ 2001 Z-28....Gone, but not forgotten!
305's run for ever because the dont make enough power to break them selfes! if its free go for it, but dont expect much even with a turbo. You can build a 350 for the same price as a 305 and have a lot more power.
you can make some good cheap power with a 305. cubic inches are cubic inches. a 302 ford or a 302 chevy never gets knocked like a 305.
The big difference there is the bore size. The Ford 302 and Chevy 302 both have a 4 inch bore as opposed to the 305's 3.736". The small bore of the 305 causes valve shrouding killing flow into the cylinders. Can you make some power with them...yes, but for the same outlay you'll make much more with a bigger bore engine.
__________________ 2001 Z-28....Gone, but not forgotten!
well the ls1's have a small bore. how do they do so well? i dont believe in the valve shrouding bs, i think there is more to the shape of the combustion chamber than anything. most people think of heads when they think of shrouding the valves. not so much bore size. ive ran that setup years ago and everyone was always impressed with the way it ran. they had to go look at the block and see the lg4 to believe it. then they looked for nitrous lines. there was none. i think its a great discussion though. alot of fun to talk about.
__________________
Last edited by 7.0 camaro; 07-02-2009 at 02:36 AM..
About to get a free mid 80s 305 Any good to play with ? 
1993 Z28 LT1 T56/M29 1.6 pro-form RRs, Fastchips, 160 t-stat, B&M short shift, Jegs opti, msd coil pack, msd super conductors, TB bypass,airfoil, all emmisions crap gone weighing in at 3100lbs
