Silver I think 455's rock.My comment regarding 300hp is aimed at the multitudes who have never experienced 300hp.............................. An experienced high performance driver (not just staight line driving, that by no means quantifys that someone can handle that sort of power) can handle this power level and beyond because they know what the car will and wont do.The other type of driver just nail it and whatever happens goes.............................. Well consider that next time someone is killed or loses it at a bend in the road, when thier car is'nt set up for it .Due to thier straight line cofidence and in certain cars 300hp is more than plenty. As much as I respect the power figures that big block engines produce on pump gas I'd never own one because they are nose heavy on the car, which affects handling and braking performance unless , its aluminium block and heads.............................. On fuel consumption 300hp will consume plenty it wont be a cheap fuel bill.And if you want fuel consumption bragging rites drive a funny car.  

300Hp can consume lots of fuel, but it doesn't have to with the right setup. The last few years of the F-bodies did pretty well for fuel at over 300Hp. The Vette is lite, but knocks out well over 20 on the highway and slightly under in the city and has well over 300Hp.  After a few more upgrades on my Skylark I plan on cruising the highways in the high 20's with probably around 350Hp (and ungodly amounts of torque).  If I wasn't concerned for mileage, I'd probably be going for a 400-500+ horse 455.  So 300Hp is only good for fuel mileage  

http://www.carnut.com/specs/engdim.html

Please refer to this page for referencing... you will begin to understand hopefully... The big block buick out weighs a smallblock chevy by 25-45 lbs... at most... with alluminum heads a big block would weigh equal to or less than a sbc probably. I understand your point and I have powerful small blocks and big blocks both.  For your reasoning though... don't underestimate a big block with a properly tuned suspension... ie: springs, bushings,sway bars, have the car scaled, adjustable control arms.... etc. The car will handle like its on rails either way. I want you to understand I am not calling you out... I just want you to have access to all the facts so you can make an educated decision that's all take care buddy and good luck with the project. silverbuick... how's the car doing?
brandon  

My Centurion successfully made the 500 mile journey back home (for those that don't know it blew a head gasket 400miles into the 500 mile trip there).  None of the pictures I took of the clearance between the A/C box and heads came out (blurry from being too close) and I didn't realize it until I got back home.  I may be heading back there next thursday because I think the Skylark is a radiator away from making the 500 mile drive.  I swapped an Edlebrock perfomer intake onto it (I can hold it out at arms length with one hand versus the stock one I have a hell of a time carrying with two hands) and got a new distributor gear for the HEI and installed the HEI on it as well.  It was running smoothly (and still loudly) when I left So. Cal, but the radiator has several small holes in it. It apparently got damaged while off the car.  I am eager to get it going for sure.

Also I've used references like that site many times for weight and size comparisons, very useful info.  With Aluminum Heads and Intake the Buick 455 is quite a bit lighter than an all Iron SBC, but I am not sure once Aluminum parts start being added to the SBC.  There's a guy here (Sams75z?? screen name) that put one in an F-body, I bet it handles the same or better now.  

I agree 300hp with a 455 is definitely a torque monster econobox! I'm also well aware that you can upgrade suspension components to handle a big block,I'm also aware of the cost! To be honest, my experience was in a chrysler,the same car with two types of V8.One a 440ci the other a 360ci.I don't know the different engine weights,however the 440 was noticeably heavier. Yeah it had more torque,but the 360 was more eager to accelerate through the rpm range quicker with less weight to pull.With the 360 small block the car weighed 3,300lbs without driver. You could also notice the weight of the BB in braking and handling,really ,it felt like a boat anchor!Both were cast iron ,factory parts, except for mild cams...........................To our original 305 man,I was checking out the erson camshafts online pdf catalog. Its great and easy to use.It has alot of cam and engine information on all engine families.Check out the hyd flat tappet TQ30. Its a great all round street cam,with dynamic torque characteristics for your 305.Later.  

TQ30???  First off its incredibly difficult to reference what cam you are talking about when there is no Sig Erson website, and no major parts dealer sells them.  Second off, the one forum I found that referenced the cam had it listed as 290 degrees advertised duration and 226 degrees @ .050.  That is INSANELY high for a 305.  Even a hopped up 305 should stay under 220 @ .050...and only if significant modifications have been made should it go anywhere over that.  Please do correct the numbers if the forum I found mis-quoted the specs.

Lets reference actual numbers from now on...rather than the name of the camshaft.  Its easier to know what you're talking about, and doesn't pigeon hole someone into one brand of camshaft.  

226 @ .050 isnot insanely high.I've seen it work well with 253ciGM V8. I will check it out myself. And it aint' a sig erson website. On GOOGLE, I typed 'erson camshafts',go. But yeah, I'd stick to 220deg @.050 with a valve lift of .470 on intake.It would require a 2,300 hi stall.But it would be nasty,with 9.5:1comp and headers, performer rpm, and 600cfm 4 barrell.Dump the pedal at cruising,you'd go sideways with 3.36gears,3spd auto.  

Unless the rest of the engine is built up...its very high.

Popular Hot Rodding's engine master's detailed a build of one...with new cylinder heads, intake, carb, headers...it was able to use 224/230 degrees duration @ .050.  Which falls in line with what I said...unless the rest of the engine is built up around it...anything over 220 degrees duration is extremely high.

For the original poster...here is how you can make 367 HP with your 305.

http://www.popularhotrodding.com/enginemasters/articles/chevrolet/0667_phrs_305_chevy_engine_blocks/engine_testing.html  

367 hp 305 now were talking. I'd still bet that even with the factory heads and a mild combo. with at least 9.5 comp. the motor should see 300hp no dramas.  

cs, i checked out that article, b/c i have 4 305's, and those are great numbers to see! thanks!  

powerdreams:
367 hp 305 now were talking. I'd still bet that even with the factory heads and a mild combo. with at least 9.5 comp. the motor should see 300hp no dramas.

I'd seriously doubt it.  305 cylinder heads are incredibly restrictive.  You'll notice in the article they jumped up to a 180 cc intake runner cylinder head.  I've seen Chevy Hi-Performance use a set of 170 cc runner S/R Torquer Heads (World Products) and get a 30 HP jump with no other modifications.

Those cylinder heads are probably the reason why 305's don't respond to bolt ons like headers and intakes.  Even a camshaft has little effect with those heads.  

mercman:
cs, i checked out that article, b/c i have 4 305's, and those are great numbers to see! thanks!

Glad it helps.  

The tq20h would be a good cam for the 305.You make it sound like the ports have been blocked off.By the way,whats the standard hp of the 305 from the factory.what are the valve sizes? the cam Ive mentioned along with the tq30 have had great success in GM produced V8's with minimal engine mods. Especially with 253ci and 304ci and 308ci engines.......................On google type 'tq30 cams'hit search and read peoples own reports of these cams and how well they perform.  

cs, i jumped over and read the article after seeing your post last night. they junked the 305 heads, went with vortec replacements with 1.94" intake valves, left the exhaust valve alone. they also used the performer rpm air gap intake and speed demon 650 carb. i do understand that a) the motors probably gonna be tapped at this point and b)the lack of accessories and a loss of power through the driveshaft hasn't been figured in. i still think this is a good combo for someone who can genuinely put it, or something like it, together on a true budget. ive probably got a similiar combo im about to put together with 87-up 350 heads, a performer rpm intake, a carter 650 carb and a .030" 305 with flat top pistons. im going to purchase the exact same cam they used, along with lifters, pushrods, and rocker arms. i may be out 4 or 500 bucks with this combo and ill have close to 300 hp in an s10. thats good stuff for having 1000 bucks in the truck total  

HunterT:
I have a firebird with a chevy 305 in it. I felt like the engine was way underpowered for the car so I was going to do a 350 engine swap but then decided against it because i want to keep the numbers matching. what could I do to this engine to make 300+ hp. can it be bored to a 350? Strocker kit maybe?

Well you certainly can't bore it to a 350. To be precise you have a 3.736 bore x 3.48 stroke. You can get away with over-boring maybe .030, even .060 if your lucky. The reason I say this, I read an earlier post here, and a car buff was saying that post-smog era engines are thinly cast compared to pre-smog era. Why? I don't know.You will need to do some reasearch there. Now back to your flow problems. My old Chilton manual rates that engine at 155 HP@ 3800 rpm, and 260 lbs.-ft.@ 2800 rpm. You currently have 8.4:1 compression. Here are some options for your problem. 1. Only swap out to a 350 if you get tired of newer Colbalt SS's and Honda Civic's blowing your doors off. You want to keep it original right? 2. Over-bore it .030, if you can afford to put alot of time and money into your car. 3. Look into some better flowing heads. Summit Racing carries a vast variety of High Performance heads, but your gonna pay for a set. Heads are not cheap. 4. Buy a stroker kit with a 400 crank. It'll fit cuz you have the same bottom-end as a 350. I have heard though that the engine needs line-bored or it'll starve for oil, once again do some research on this. The precision balanced 400 crank will easily rev past 5000rpm, depending on what kind of crank you buy, and it will GREATLY increase your torque thoughout your ENTIRE rpm range. 5. Induction: I recommend Edelbrock's Performer-RPM package as well. I have used their Performer series porducts on my Malibu and had excellent returns, for what I wanted to do with my engine. As far as Exhaust??? Flowmaster all the way, and you'll want ceramic coated headers, but don't go overkill with a set of 4" pipes and HUGE port sizes on the header. This is a conservative engine that WILL NOT respond to full race aplications like a 350, a 302, or a 327. I doubt anyone will read this entire post, but don't get discouraged. You might see 300 HP at the crank, but not at the rear tires. Remember you are building a small V-8 with restrictive bore and restrictive heads. Gib TG is rough on his posts, but he is right about one thing, ALL the tuning you do to this engine must work in synch. A 1200 cfm carb is not gonna benefit you anymore than a huge cam with like a .570 lift and 288 duration @ .050, without an engine, and tuning required to handle it. * That last statement was an example of how people can go overkill when they don't know how to properly tune an engine. There probably isn't a camshaft with those exact specs, I just pulled those numbers out of the air.