305 V8 Motor (5.0) Mods? -- Emissions Legal!
cknight725
05-16-2002, 01:47 AM
If I've learned anything from reading other websites its that the 305 and 350 respond very differently to generic "Small Block" aftermarket parts...
THE PLAN:
Anyway --- I've got an 84 El Camino with a bone stock 305 V8 -- I've got a budget for some mods like cam, intake, headers, exhaust etc, but I have to still pass emissions. The PO already installed a Jacobs' Multi-Spark ignition system with the HEI dizzy. So the question becomes, which mods -SPECIFICALLY - are going to yield the best bang for the buck? I'm figuring on swapping the stock 84 Quadrajet for a Holley Stret Avenger 600cfm, maybe either a Performer or a Torquer II Manifold (street cars like torque more than HP), a set of Edelbrock EGR Headers ($350!!) then a 2.5 inch dual high-flow cat, dual exit exhaust running through a set of Flowmasters.
CONCERNS:
All in all not radical, but will it be worthwhile? Has anyone used Edelbrock's emissions legal camshafts? Did it really improve anything with the stock heads on a 305? How about the stock intake manifold -- would it be worthwhile to use it with the Holley Carb, or is the intake the restrictor? I'm pretty confident that the exhaust / header swap is a good investment, but has anyone had their own experiences with high-flow cat's?
Basically this is my first V8 project, I've got access to other muscle carsin the family that have been tuned, but none of those have 305's that have to pass emissions, my Hi-Po Aircooled VW experience doesn't help much either ...
THE PLAN:
Anyway --- I've got an 84 El Camino with a bone stock 305 V8 -- I've got a budget for some mods like cam, intake, headers, exhaust etc, but I have to still pass emissions. The PO already installed a Jacobs' Multi-Spark ignition system with the HEI dizzy. So the question becomes, which mods -SPECIFICALLY - are going to yield the best bang for the buck? I'm figuring on swapping the stock 84 Quadrajet for a Holley Stret Avenger 600cfm, maybe either a Performer or a Torquer II Manifold (street cars like torque more than HP), a set of Edelbrock EGR Headers ($350!!) then a 2.5 inch dual high-flow cat, dual exit exhaust running through a set of Flowmasters.
CONCERNS:
All in all not radical, but will it be worthwhile? Has anyone used Edelbrock's emissions legal camshafts? Did it really improve anything with the stock heads on a 305? How about the stock intake manifold -- would it be worthwhile to use it with the Holley Carb, or is the intake the restrictor? I'm pretty confident that the exhaust / header swap is a good investment, but has anyone had their own experiences with high-flow cat's?
Basically this is my first V8 project, I've got access to other muscle carsin the family that have been tuned, but none of those have 305's that have to pass emissions, my Hi-Po Aircooled VW experience doesn't help much either ...
curtis73
12-11-2002, 12:15 AM
I know this is a generic reply that you'll hear a thousand times. Since a 350 is externally identical to a 305 in appearance, its the best bang-for-buck swap. The 305's biggest weakness is in the heads since they were all produced as the wimpy fuel-efficient alternative V8. Porting 305 heads is pretty useless and using 350 heads will only yield sub-pathetic compression and shrouded valves (or even valve contact with the walls). In order to get good performance from a 305 you will most likely spend more than if you buy a $699 Recon 350 from a parts strore and add your own performance parts. Everything on your 305 is pretty well tuned for the pathetic power it makes, meaning that upgrading one component will make the rest of them restrictive. Just a head change wont do it. It would take a better intake, heads, cam, valves, exhaust, and compression, and then you would be left with a well-tuned small bore, small displacement engine.
I'd absolutely stick with the Q-jet if you want it to pass emissions. The street avenger may only be legal on 1980 and older vehicles (depending on your local laws). The Q-jet also runs cleaner and delivers much better MPGs and (when tuned right) makes killer power. I am a big fan of Q-jets because they're great. It will also be required because your Q-jet is partially controlled by the computer.
Stick with the Performer intake. Both the RPM and Torker are not emissions legal and also WAY more intake than you can use on a mild street engine. The name Torker implies torque, but not streetable torque. Suffice it to say that a Torker manifold will start thinking about making torque somewhere way above your current redline, meaning your streetable torque will be absent. Not just wimpy... non-existent.
Keep the cam in the 195-215 -at-50 duration in a 350, 190-205 for the 305. Any more and your idle hydrocarbons will be sky high.
Your carb isn't too restrictive. That Q-jet is probably a 625 CFM, which I have used on as much as a Caddy 500 CI putting out 350 hp. It was a little restrictive, but not too much because my redline was only 3500 rpm.
Buy a parts-store 350 with iron heads and a mild hydraulic roller cam, put a performer intake and have your Q-jet retuned by Jet Performance or a local shop. Your 305 most likely is putting out about 125-140 hp. A 350 like above will be more like 250 hp. If you're careful about where you find your parts (reground cam instead of new, swap meet intake, re-use your old components, etc) you can get by pretty cheap. I did a 350 like this for $1500 total investment. Of course I had a core to trade in, too.
Keeping the stock exhaust manifolds will help emissions but hurt power a little. 2.5" exhaust will be overkill and may cause a little loss of low end torque, but thats up to you. You may also not like the droning of the exhaust, but that can be helped with good mufflers like Flowmaster Delta Flow series 50 three-chamber units. If you get it all together and find that you are way within cold-start emissions limits, then swap to headers. The heat retained by the manifolds helps the cat heat up faster.
Good luck, all opinion, take with grain of salt.
Curtis
I'd absolutely stick with the Q-jet if you want it to pass emissions. The street avenger may only be legal on 1980 and older vehicles (depending on your local laws). The Q-jet also runs cleaner and delivers much better MPGs and (when tuned right) makes killer power. I am a big fan of Q-jets because they're great. It will also be required because your Q-jet is partially controlled by the computer.
Stick with the Performer intake. Both the RPM and Torker are not emissions legal and also WAY more intake than you can use on a mild street engine. The name Torker implies torque, but not streetable torque. Suffice it to say that a Torker manifold will start thinking about making torque somewhere way above your current redline, meaning your streetable torque will be absent. Not just wimpy... non-existent.
Keep the cam in the 195-215 -at-50 duration in a 350, 190-205 for the 305. Any more and your idle hydrocarbons will be sky high.
Your carb isn't too restrictive. That Q-jet is probably a 625 CFM, which I have used on as much as a Caddy 500 CI putting out 350 hp. It was a little restrictive, but not too much because my redline was only 3500 rpm.
Buy a parts-store 350 with iron heads and a mild hydraulic roller cam, put a performer intake and have your Q-jet retuned by Jet Performance or a local shop. Your 305 most likely is putting out about 125-140 hp. A 350 like above will be more like 250 hp. If you're careful about where you find your parts (reground cam instead of new, swap meet intake, re-use your old components, etc) you can get by pretty cheap. I did a 350 like this for $1500 total investment. Of course I had a core to trade in, too.
Keeping the stock exhaust manifolds will help emissions but hurt power a little. 2.5" exhaust will be overkill and may cause a little loss of low end torque, but thats up to you. You may also not like the droning of the exhaust, but that can be helped with good mufflers like Flowmaster Delta Flow series 50 three-chamber units. If you get it all together and find that you are way within cold-start emissions limits, then swap to headers. The heat retained by the manifolds helps the cat heat up faster.
Good luck, all opinion, take with grain of salt.
Curtis
79elcaminoss355
06-02-2005, 02:17 AM
not sure what your laws are for emissions but if you want to saty with a 305 they do make stroker kits you can buy for them to make them a 335 ive seen a couple of them pushing close to 300 hp i think the kits were around 1000.00 and then what ever the machine is
wafrederick
06-02-2005, 03:39 PM
Put a 350 in it's place.A 305 is not worth anything.Stay away from a Recon(PILE OF JUNK!),buy one from GM,from the dealer or Jasper.
wafrederick
06-02-2005, 03:50 PM
Edelbrock does sell a 350 crate engine complete with the heads intake,waterpump with a carberator or fuel injection.
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