[malibuman400]

A family friend wants to freshen up his 305 in a 83 Firebird. He would like a cam swap and maybe heads. This is strictly a cruzing car no track time at all.

For the cam I recommended A summit 262/272

If he wants heads I think the basic Vortec heads would be a good choice with a Vortec Performer intake.

I have no idea what carb to suggest for his smog 305.

Any ideas, criticisms, or comments would be appreciated.

 

[Dave427]

A good ole 1850 600 vacuum secondary.

Dave

 

[novaderrik]

keep the q-jet- the best carb ever built. but put a better intake under it- i'd say an Edelbrock Performer to keep the smog police happy.
vortec heads will lower the compression on an otherwise stock 305- which probably offsets any gains in airflow from the better heads. if he has an L69, he has about the best heads on it that ever were put on a 305.
i don't know how the computer will react to that particular cam and what it might do to the emissions output. but it might work out ok.
i'd spend the money where it will make the most difference- get all new exhaust for it. new headers, new high flow cat and at least 3" exhaust all the way out the back. build some sort of a cold air kit that rams lots of cold air into the carb. if that makes it run better, look at deeper gears in the rear end. 3.42 or 3.73 gears would make that a fun little car.

 

[BACK FROM THE DEAD]

for all the hassle he's going to go through to swap all that stuff, he may as well put in a 350 while he is at it. since all he'll be re-using (engine wise) is the block crank, and rods.
he could even re-use the 305 crank in a 350 block. and then swap over all if his accessories (fuel pump,alt.,P/S pump, exhaust manifolds...ect).
the Vortec heads and a cam in a 350 would be really fun in that car.

PS: if the smog test is an issue for the car, the vortec heads will blow it for him, as they do not have an EGR cross over, and cannot support an EGR system.

305's suck! he will regret it if he puts all that effort into it when he could have had a 350. even with those mods the 305 will still be a disappointment. i'm not just saying this to bash on them. i've had them, stock and modded, and they just aren't worth it if you want HP.:yes:

 

[71malibu406]

for all the hassle he's going to go through to swap all that stuff, he may as well put in a 350 while he is at it. since all he'll be re-using (engine wise) is the block crank, and rods.
he could even re-use the 305 crank in a 350 block. and then swap over all if his accessories (fuel pump,alt.,P/S pump, exhaust manifolds...ect).
the Vortec heads and a cam in a 350 would be really fun in that car.

PS: if the smog test is an issue for the car, the vortec heads will blow it for him, as they do not have an EGR cross over, and cannot support an EGR system.

305's suck! he will regret it if he puts all that effort into it when he could have had a 350. even with those mods the 305 will still be a disappointment. i'm not just saying this to bash on them. i've had them, stock and modded, and they just aren't worth it if you want HP.:yes:

i would have to agree 100%. the 305 is a good reliable daily driver engine that is pretty fuel efficient for a V-8 in stock form. you start modding it with a different cam a holley carb, deeper gears, then you just kill the only thing it was good at, mpg. if you want power then look for a 327, 350, 400....or any combination there of.

 

[Guest]

Have a good read b/c I saved this through the years just for guys that want to do a 305!

"I found the old article telling about the maxed out combo for a 305 so here goes. It was in Hot Rod Action Series Volume 2, Number 1, early 1984 booklet.

They started w/ a stock 9.5 to 1 CR. shortblock, cast pistons and all! Then added 350 rods b/c the 305's are too skinny!!

They made a 10.6 CR. 305 using -041 number heads that were reworked to 59 cc w/ 1.94"/1.5" valves. Deck height is .035" w/ a stock 305 head gasket, so is close to say the least! Intake ports were untouched w/ only bowl work done. They taped up the pistons and ground some exhaust valve clearance so the valves had enough room! Did some bowl work on the exhausts too. Manley Pro-Flo valves.

The cam was a CC magnum 292H w/ 244 duration at .050", 110 lobe centers and 501" lift. They used .100" shorter pushrods to correct the valve train geometry.

Headers were 1.75" four tube w/ 23" collectors and a pair of Supreme Super C turbo mufflers!

Carburetion was a Victor Jr. and a reworked 650cfm Holley double-pumper!

Ignition was an MSD-6A and an MSD extra duty distributor(?). A 4" K&N filter. A windage tray and crank scraper in the pan!

Here are the Engine dyno numbers!

3500rpm - 210hp -- 314t - .398 BSFC
4000 - 243 -- 319 - .394
4500 - 270 -- 320 - .411
5000 - 316 -- 331 - .417
5500 - 361 -- 344 - .419
6000 - 376 -- 335 - .444
6500 - 378 -- 305 - .451
6850 - 386 -- 296 - .461
7200 - 402 -- 287 - .479

Here it is!!

From a 1995 Chevy High Performance article.

305 Engine Build-up.

1 ’69, 041 double hump 1.94”/1.50” valve heads cut to 59 cc’s. Bowls blended and only the exhaust ports polished.
2. Manley Pro-Flo valves, PN 11560 intakes and PN 11559 exhausts.
3. CC 292 Magnum hydraulic cam, 292/244, 110/106, .501” lift.
4. 350 rods rebuilt with good bolts and nuts.
5. L-69, 9.5 to 1 CR. LU5 fuel injection short-block engine with stock head-gasket gives 10.6 to 1 CR. Or a
6. LG4, 8.6 to 1 CR. engine will give 9+ to 1 CR.
7. Deck height was .014” down with stock four valve notch cast pistons.
8. Quench was about .035”.
9. Hooker 1.75” four tube long headers with 3.0” collectors. PN 2110 for a Third Gen. car.
10. Holley 650 double pumper PN 4777 and an E-brock Victor Jr. intake.
11. 4” K&N open filter.
12. Good Electronic ignition

The little bugger made like 402hp up top!! They ran it until she spun a bearing or just came unglued!

AND

An old RHS, Memphis, TN, 305 motor build-up that makes right at 300hp. http://www.goingfaster.com/spo/290hp305.html
Chasis Dyno Test
7000rpm --- 300hp

And Hotrodding the 305!
http://www.goingfaster.com/spo/modthel03.html

And an article from mw66nova
http://www.thirdgen.org/techboard/organized-drag-racing-autocross/394788-new-bests-two-walter.html
new bests for two Walter Racecraft 305's!

well, Kody and I were able to get out to the track for one more night of racing tonight before we called it a season. i was totally stoaked at the times we got as i totally didn't think we were going to do as well as we did. remember, these cars are 100% daily driven and 100% naturally aspirated. race weight for Kody's car with him in it: 3255, race weight of my car with me in it: 3220

i'll start with Kody's car cause i haven't really told many folks about it. combo is super simple:
-305 out of ssean92's 1992 RS
-416 casting heads with backcut valves
-lt1 cam
-crane energizer aluminum roller rockers
-hedman longtubes with manderal bent y-pipe into a 2.5" dynomax catback with homemade cutout
-holley street dominator intake (the smaller of the two, basically a performer) and an edelbrock 1406
-2100 stall converter w/ 700r4 and 3.23's with a 275/50/15 mt ET Street Radial.

previous best was in the upper 15.2x range, tonight with the cool air it went 14.67@93.7mph. we went from a 28" tire to a 26" tire and rebuilt the carb and added more timing. the car needs some more gear bad. timeslip for that pass looked like this:
r/t: -.123
60': 2.205
330': 6.166
1/8: 9.441
mph: 75.20
1000': 12.276
1/4: 14.678
mph: 93.73

we were hoping for some 14.9's, so to get a high 14.6 out of the car was like walking on sunshine.

now for my car. alot of you know that the solid camshaft that was in the car was hurt and i put in a used 280H cam that my friend Eric gave me. i totally didnt' expect to even break into the 12's and i did that at the shootout we had back in the end of september with a 12.97 @ 103mph. air was SUPER nasty that weekend and i was trying to run a 13.0 index class so i wasn't looking to go blazingly fast anyhow. the previous best for my car with the solid cam in the 305 back in may was a 12.50@106.8mph. that was with hotter weather, a water pump drive kit and manual steering. this evening the car had full accessories (water pump, alt., and i put the powersteering back on) so i was going to be happy with 12.7's. i figured that would be possible because of the cool air. after screwing around on a few runs trying to get reaquanted, i clicked off a 12.42@107.49mph! the timeslip for that pass looked like this:

r/t: .088
60': 1.694
330': 5.035
1/8: 7.862
mph: 86.33
1000': 10.328
1/4: 12.425
mph: 107.49

after that pass we decided to see how fast we could actually get the car to go. i knew that the powersteering was worth atleast .1 so i snatched the ps pump belt off the car and proceeded to go 12.39, followed by a 12.34, and then finally a 12.31@108.48mph!!! that pass looked like this:

r/t: .150
60': 1.678
330': 4.994
1/8: 7.797
mph: 87.05
1000': 10.240
1/4: 12.318
mph: 108.48

as you can tell, i'm so pumped about it that im writing a thread about it at 1:18am to tell ya'll. anyhow let me know what ya think. oh, and check out a pick of Kody's ride all ready for the track wearing the mickey t's!"

pdq67

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[ZZ69chevelle]

I'd stick with the Qjet. I did a few basic things to my 88 Camaro's 305 to wake it up. Mostly better heads, LT1 cam, headers and exhaust, and it really woke up with no adverse affect on fuel mileage.