Hi everyone. I know it's not the block of choice, but I was curious who has the fastest 3rd gen 305 based car?

Someone out there should be better than this, but mine runs 14.5's n/a and 12.2 with turbo in sig pushing 13psi.

mw66nova was running 12.3's n/a.. i'm pretty sure the comp eliminator guys have been mid 11's. but i dont think they run a true 305 block 305 but instead a destroked 350.

negative, the super stockers have been 10.7x's or so on an n/a .060" over 305 block with "untouched" 416 heads. but you gotta look at the total package. those cars are completely unstreetable with huge duration and narrow lsa camshafts, 5500+ converters, and 5.13+ gears.

going 12's n/a is pretty easy. i went 12.3x's with a street/strip setup, but i was using some old school single grind camshaft and i know that i coulda gone faster with a new technology solid roller camshaft, but we weren't ever able to make it happen.

Preston had the fastest documented tradtitional small bore streetable 305 combo back in the day. car ran low 10's/high 9's on high boost and got 20+mpg with a street tune. it was a tuned port combo if i remember correctly. last i heard he is running a 4.025" bore/3" stroke combo that nets him 305 cubes but still has a big bore, big cylinder head, and big turbo...the car is faster but not by much. don't even know if he's around still.

we gotta new guy in the 305 club, can't remember his name. he's got a firebird, with a t56. he's been upper 12's n/a, low 11's on a 200 shot, and now he's running a blower, has been 11.99 with the blower, and he just put a 100 shot back on it, but not sure if he's tried it out yet at the track.

yup, crazy stuff. i was thinking since my 385 spit out a rod, to do a wild 305 combo. i figure if people can build a 9 sec n/a 400+sbc, why not a low 11 sec 305?


since i have two nice 305 blocks already. my heads are trashed and way too big anyway, so maybe afr 180 eliminators? decent size solid roller(mid .550's, 235-240 duration, 108lsa), 6" rods, ported rpm airgap, and a 650 carb. would be pretty impressive to be running with the big boys with a "rebuilt" 305. haha

or i could use the old camel backs i had from my first motor. i did a nice port job on them. took my 383 into the 12's with a smaller cam and a 650 carb.

11.50s at 116 on my old 305 with a 150 shot. was good for 13.0-13.1 at 102/103 on motor. Definitely nothing crazy out of it, this was at least 8 years ago I'd imagine.

I'd like 13's (13.0-13.9) out of my tbi, and with the wynjammer SC, 100 shot, and lots of weight reduction (plan to get car around 2800 meaning a drop of 600lbs roughly, in which I have already dropped over 150 in the engine bay alone and still have lots to lighten in there) I think 13's are very reasonable. I don't care for a straight line like most of you, which is why 13's is just fine as I plan to slide my Roxie around turns, so suspension and weight is more in my vision than power. Also if I can get even better than my already 18mpg I get now or stay the same in doing all this I'll be a super happy camper. But I would like to see some of these LO3, LG4, L69 and LB9's go. Videos anyone? Pictures of these motors?

-Take care

there is a local guy with a black formula...i hadn't heard a supercharger on it lately, but he was running a 200 shot banging the gears...beautiful car too. he had 350 high perf. heads of some type on it. hopefully he'll chime in...

i guess your talking about me 86iroc, i just put a weiand 142 on a few weeks ago, i went a 11.990 with a real fat tune and only 26 deggres of timing to be safe, i plan on taking it to the dyno up in fallston sometime this week or next and get it tuned, im hopeing to run mid 11s, then see what the 100 shot on top the blower will do, maybe high 10s. The fastest i ever went all motor was a 12.48 at 109 last halloween in low 40 deggree weather

I know of a Super Stock Monte that runs 6.50's in the 1/8... Flattop pistons, .700" lift cam, single plane intake of some sort with a QuadraJet, 1-7/8" headers with merge collectors, 416 heads must maintain stock runner volume of 163cc with 1.84/1.50" valves....Makes 538HP at 7800rpm...goes through the 1/4 around 8800rpm... his name is Larry Hodge...

yea ^^ you were the one....ive seen you around car shows and the track this year in my truck. congrats on the blower...ill catch up with you soon....


as for 305 builds...there are a lot of stockers out there running 10's...and im really looking forward to building one SOON!!!

mw66nova had one of the cleanest and fastest street/strip 305's ever IMHO.

mine started out as an lg4 in a base model 85 z28.



mid 12 second pass, not sure what it ran on this pass:

And who said u can't do anything with a 305?

Nice, and you still have some weight reduction you could do as well. Nice run.

It depends on exactly how far you want to go for weight reduction. My car now sits at 2860lbs "race weight" without me in it and I still have the stock"ish" suspension and iron heads on it. I can't wait till I get the coilovers/tubular frontend and put the ZZ4's on. That should put me in the high 2600, mid 2700 range. Hell if I could find one I'd drop in an LS1 and shave off that extra 150lbs I keep hearing about,lol

I'm still tuning in my car right now and I'm getting alittle better at it but from what the EBL is telling me I should be in the mid to low 13's. I'm now working on my WOT .I know the biggest thing I do have going for me is the weight advantage.

86Iroc2try- I love your tow rig, primer and stickers rule! You need a push bumper about 2' wide with old snowmobile track on it for rubber, and some old school lettering hand painted on the doors so it looks like the old push trucks push starting the front engine rails back in the 60's!

And I am proud to say the single pattern cam MW66Nova was using was a used comp 280H that came out of a core 406 I bought. Glad to see it lived on and worked well.

eric! it's still living, the beastily 305 is back in my dad's car now, funny how that worked out, eh?

so i went back to the track last night, first pass i went a 11.81 at 117 with a 1.628 60ft, i didnt use the nitrous cause my fuel pressure kept on dropping to 3-4 lbs by the end of the track, after that i started messing with the timing and only went a 12.01-12.3 on the last three passes. i have videos of all 4 runs, ill try to upload them

I like your set up. 305 with T56 is not so common.

what size valves are in those pro comp heads, didn't know they made anything compatible with the 3.736 bore.

from what i've saw they all seem to be 2.02/1.6 valved as a minimum, i'm confused and interested lol.

yea there 2.02/1.60 valves

well what is the valve spacing then..... I've never heard of valves spaced that closely together to fit a 305 ..... is yours overbored? just trying to understand this fully lol.....

i had my old 305 running 13.80 wit pretty much little things done nothing major

its bored .30 over and the valve spaceing is what ever a standard sbc is, there supposed to fit a 283-400 sbc

my basically stock iroc with a 100 shot and long tube headers goes 8.6x in the eighth

I also have a Procharged 305. No track or dyno times yet though. Im hoping its a mid 12sec car. But IDK, shes a fat pig, No weight reduction at all, actually alot of weight adding. Its more of a road warrior than a track car though. It whips on alot of 4th gens and Mustangs regularly. I also have an L98 sitting around, considering a boosted 383 TPI.

I thought that you're running a 383.. what turbo are you using on the 305? Build thread/details somewhere?

as far as I've heard (and I believe that I asked him once), Preston has never run an actual 305 combo, just the large bore setup first with a supercharger then a turbo.

Did you clearance/notch the top of the cylinder bore or do anything else unusual to make the valves clear? If not, normally they'd hit, they have to be close unless you're running a tiny camshaft (huh... I have a set of canfield heads that I've been saving for a larger engine, but maybe I should see if Ic an get them to work on the 305...)

FWIW, I'm hoping to find the time and the space to work on it to give it a try with my '87 LB9 next year. Right now I need to pull the stock heads and clean them up (shot valve guides, smokes pretty well) and I have a couple of medium sized cams that I can try in it sitting around, otherwise I'll probably ditch the TPI manifold and replace it with a victor jr that I converted to efi for a 350, just because I hate working on the TPI. The rest of it I'm going to do the hard way, since when I tried to buy a new project car the one that I stumbled on had all sorts of options that actually worked, including a working AC that someone converted to the new stuff, which at this point I'm thinking of keeping- the car is in the 34xxlb range + 300# of me in it, and I can see where I can strip a few lbs from that total, I'll probably add as much trying to make things work (and stay legal) as I add power.

The Super Stock 305's have well massaged heads and any cam is allowed. Those guys are well into the tens. There have so far only been 2 305 Stockers in the tens; Brian Van Poppel and Dave Casey. My own best so far is 11.02 @ 118 (6.91 @ 96 in the 1/8th) and I'm hoping for better next season.

[quote=83 Crossfire TA;4366351]




Did you clearance/notch the top of the cylinder bore or do anything else unusual to make the valves clear? If not, normally they'd hit, they have to be close unless you're running a tiny camshaft (huh... I have a set of canfield heads that I've been saving for a larger engine, but maybe I should see if Ic an get them to work on the 305...)


nope i just bolted the heads on and they worked, i have a comp hr276 cam with 1.65 rockers so its not a huge cam, but its not very small

Didnt Brian change classes, i think hes running super stock now, i saw him in the low 10's over the summer up at cecil.

I am running a 383, but one time it was blown up and getting fixed I swapped long blocks for the hell of it to see what the 305 could do.

Yes Brian is now running Super Stock, the time I mentioned he was running G/SA still. Dave Casey was running G/S.

Mod313, was youre car ever in camaro Perfomers magazine? Looks familiar.

so it sounds a hell of a lot like (ignoring the super stock cars) getting deep into the 12's would get you in a pretty rare group, and getting into the high 11's would put you in a group with 1 or 2 others. Sounds like I have a target to shoot at...

89305formula, is your car a street car? Sounds like it might be getting towards that edge where "yea, it could be street driven but..." What tracks do you usually run at? I used to run at capitol almost every friday night, but haven't had time to do it for a few years now (I think I've only been once or twice in the last few years).

Huh, I have a CC 224/224/114 roller cam sitting around, not sure that that is going to be competitive without either a lot of boost or spray (or both), especially if I stay with the factory heads and close to the factory weight. I'm debating spending actual money on this 305 now instead of just seeing how fast I can go with what I have sitting around... grrr...

the only people i know that are going 11's that aren't stock eliminator cars are either boosted or juiced. bottom 12's are about the best i think you'd do with a "street" car n/a.

i wished i had had the 305 in this past fall when the weather got cool...i'd imagine that it would have gone 12.1x's or better.

heh... I don't have the patience to do an NA car right now... I haven't welded anything cool in a while and feel like using the Bridgeport for something... I think I'm going to make some custom pieces and throw an HX52 or GT4202 at a very close to stock long block and see what I get, and if that doesn't move it fast enough I have a full 15# bottle sitting in the corner that doesn't seem to have a home.

As of right now I think that the best pass this thing has ever made was in the 15's... it was really sad...

Ive wanted to do this for awhile, just to piss off the naysayers.

A big boost, or big shot true 305. Id even keep a tbi, just an aftermarket kit.

One day, after I build the firebird up the way I want, I might buy another 3rd gen, and build a screaming 305.

Not that I know of. Maybe you saw it at Lebanon Valley?

yea its a street car, i drive it almost everyday if its nice out and can get about 14mpg around town if i drive it real easy. I usually race at cecil county and wednesday and friday nites, i only go to capitol for the jasper shootout but i didnt make it this year due to a slipping clutch, I dont really like capitol that much cause the up hill stageing lanes get old real quick with a stick car and the pot holes in the parking lot can swallow a whole car.

yea^^ i remember you talking about those uphill lanes.

and Brian Van Poppel is running 10's with a stock elim legal car...uncut fenders, etc. he switched from a quadrajet to FAST fuel injection.

Brian does a lot of work on my car with me. Those stockers aside.....

SOMEBODY has to build a 10 sec n/a 305 motor one day..."street driven." hahaha

you know, I never even thought about it... I think 75&80 are pretty much flat on average, but a lot of people think the track is uphill (I'm pretty sure it's not really uphill till you get past the 1/4 mile mark). MIR I'm pretty sure is downhill in the lanes but uphill from the lanes to the track... Why is it a problem? I always kind of liked it at capitol, made it easy to get your car out when something melts or falls appart between runs. I always liked the fact that capitol has a bunch of staging lanes so if it's buisy you have some idea how long you have to get ready...

I don't see why it couldn't happen if you're careful... I just have different goals for the car, and the fact is you could put a supercharger, turbo and N2O on a 305 around here and people will still expect you to run 13's....

well the uphill lanes are an issue when you gotta start the car every time your line moves, as opposed to being able to drift down the lanes.


And the only real reason nobody builds a 10-sec N/A 305 is the money...the same parts on a 350 or 400 make wayy more power.

the reason i dont like the up hill lanes is i end up heating the clutch up before i get to run and it ususally ends up slipping

heh... maybe you need a better clutch (coming from someone that got tired of the sketchy clutch in his '97 WS6, swapping in a Mcleod twin and realizing that I hated that clutch worse, and then it blew up instead of just slipping... now I have a centerforce which seems OK).

That would explain why I never noticed or cared... I usually try to get there early and get towards the front of the lane, then come straight back into the lane as soon as I run, so after a run or 2 you end up at the front of the lane, so when your lane starts going you get enough warning that you're about to go when they start hooking and unhooking the chains, but you get to pull straight into the burnout box so you don't get a chance to heat up. You get consistently better runs that way.

I think Mr. Bain (nape) has the fastest 305 American Iron car.