Well the key to building a preformance motor is a bore to stroke ratio, because heads and intake can always be changed. That is where the 305 fails miserably. the reason for this is in a OHV motor you need a maximum amount of valve, which is determined by the cylinder size, bigger the cylinder the bigger the valves can be. Examples include the 307 and 302, both derived from the bore and strokes 283 and 327. The smaller bores like the 283/307 at 1.94 for the intake, cant fit big valves, but the big bores like the 302/327/350 and 383 can fit the 2.02's. Anouther thing to consider is that the longer the stroke the more stress is put on a bottom end, so that creates stories of race 283's and 302's pulling 10'k for a decent amount of time, conditions that the longer stroke motors like the 305's 350's and 383's cant live at. So what am i saying?? the 305 has a crappy bore to stroke ratio, one of the WORST sbc's of all time for a high rpm HP type motor, BUT the longer stroke torque is actually better for a street rig because it is more usable power with a bore to stroke ratio comparable to a 383 stroker But that is my opinion
305 are low performance motors from the factory, small valves, low compression, and a small bore. it will cost more to increase performance than most of the other chevy v8's, if your just wanting a mild small block and don't care about beefing it up a 305 do the job just fine. my first model A had a 305 in it and ran good, was even decent at the track. But, after I put the 327 in it, it was night and day difference. It's a fine motor if you get a deal on it but if your going to be building a motor it would be silly to do a 305 over almost any of the other sizes of small block chevys
i agree, some numbers just don't "sound" right... but just for kicks....http://denver.craigslist.org/pts/2010813184.html thought you'd get a laff... btw, there's a lot of stock class drag cars running 305's....
305 and 350 cost the same to build .I have a 305 ,That one day Ill use as is .Also have a 350 that needs rebuild ......
the heads cat be that bad. 99% of the dirt guy run them on 350s around here. Alot of them wth no machine work. Aguy at work run in a sprint car class (ithink) that is regulated to 305s to keep cost down, he built a new motor for this year that dynoed at over 550 hp for almost nothing. The guys in this class know what to do to them for cheap power that usally last all season.
5L inboard hydros run stock early 305s with small valve early heads no roller or after market cam stock two brl intake and a holley two brl. and dyno at 270-280hp and they turn them at 62-6400 rpm the hardest part to find is a 305 specific head gasket most gasket sets are for 4" bore. newer vortec 305 would be better and one with a quadrajet would get good gas mileage. and don't put in a 350 cam it will be a dog, no torque
I put a pretty healthy cam in one of my 305's and it runs hard,and it seems to have even better torque than stock. Any motor can be over-cammed,though.
Bullshit! We build 305 sprint car motors. They run 2.02/1.60 valve, 200cc runner heads (World or RHS are both really common). With flat top pistons, solid cams and Hilborn injection we are getting 550HP on the dyno with no problems. We put good rods (Crower), JE Pistons, 4340 cranks and turn them mid 7000's all season without problem. We have done 4 bolt conversions (not worth the work) or simple steel straps on the main caps and never lost a bottom end. The class is limited by block casting numbers and wet sump solid cam rules. They are fine, how many of you actually race your rod? SPark
So it sounds like they are running a stock 160 net hp 305,put on a bigger carb and get 100 more HP? That's some serious tuning....
1987 305 HO out of Monte Carlo SS, radiator to trans tailshaft all complete 350.00 2/56 rear gear plenty of takeoff and 200 metric for the road Very satisfied with this combo Gus
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I've heard of people knotching the block, something to remember about that though is the closer the edge of the valve is to the cylinder, the less it breathes. In a '57 small block chev book don francisco said something to the effect of valves over 1 15/16" were pointless even in drag motors, and at that time people were building small blocks regularly up to 327 and 350 cubes As for performance 307's they were popular in the late 50's because you could throw a stroker crank in a 283 and get more cubes, and there aint no replacement for displacement, my 64 M/T catolog even shows something like a 4" stroker crank
Best way to tell is to bolt a head on a bare block.. Use a thin wire spring to hold the intake valve in place... turn the block upside down then push the intake inward to view how much cyl. wall too valve edge clearance you have... Piece of cake!
so if you didn't have a class restriction limiting you to using a 305, would you use a 305 over a 350 for a performance based motor?
Bingo we have a winner. The main reason that the 305 engines haven't got the popularity besides being short 45 cubes to begin with is that hard parts cost a fair percentage more. Go to any online source for engine parts and price out comparative short block pieces for a 305 and a 350. Machine work should be exactly the same. Bolt on goodies are the same usually the pistons and rings cost a fair amount more for the 305 than for a 350 with equivalent parts from the same manufacture and vendor. You can do the same check on any sbc from the 262 Monza engines on up to 400's and the results will be the same. I just hauled a 305 shortblock off for scrap because I didn't get one call on a Craigslist add where the asking price was 50.00. Not even one call from a lowballer. Any cash in hand offer would have owned it.
Truckedup- block 0 deck .035 between top of piston and head .030 oversize stock replacement pistons(dished) file fit rings, three angle valve job stock replacement small valves no back cut no proflow necked down stems 45degree valve seats no porting or intake matching stock aluminum or cast iron two brl intake all the timing in by 3000 rpm stock crank no lightening stock flat tappet cam only one allowed and topped with a holley 500cfm 2 brl no secrets and the boat won the Canadian and North American championships
Too bad you didn't live over here....every schmoe and his mother wants $300 for the damn things. NO SUCH THING as a cheap engine in Dirty Jersey.
i have a 305 im puttin in my 52 i got the car for $100 78 nova kept motor and tranny sold off rest to guy for stock car for $50 the old lady that had it didnt drive it her husband did up until he died i drove the car home rusty as hell from sittin but went like hell on the open road i have ram horns for it and a q-jet and i put a stock cast 4-bl intake i just want a cruzer hookin it to a s10 4x4 rear posi 3 something for gears what would be good set of older heads to put on??have a few sets i just want something i can get in turn the key and go
Im gonna use one in my next build .If I decide to build one.....I have 2 cars to finish first ............I have one spare
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