325 horsepower 305 cid Chevrolet V8
(Built with simple bolt on mods!)
This information is a brief summary of an article that appeared in the March 1999 issue of Car Craft magazine.
If you are seriously interested in this build-up, I suggest that you find a copy of that issue.
305 BUILD-UP PART 1.
Car Craft started out with an 80,000 mile (130,000km) 305 LG4 engine from a 1982 Camaro. They removed the engine from the Camaro and put it straight on the dyno with headers, 3" dual pipes to Flowmaster mufflers, and a HEI distributor with 22 deg total advance. This gave a baseline dyno result of:
197 HP @ 4,000 rpm. 261 ft/lb torque @ 3,100 rpm.
305 BUILD-UP PART 2.
Added an Edelbrock Performer EGR intake manifold, but with the EGR blocked off.
217 HP @ 4,200 rpm. 285 ft/lb torque @ 3,300 rpm.
This is an increase of 20 HP and 24 ft/lbs over stock.
305 BUILD-UP PART 3.
Replaced Edelbrock Performer EGR intake with an Edelbrock Victor Jr single plane intake manifold. Replaced Q-Jet carb with a 750 Holley double pumper.
217 HP @ 4,200 rpm. 285 ft/lb torque @ 3,300 rpm.
This resulted in no change from the previous mods, maintaining the increase of 20 HP and 24 ft/lbs over stock.
305 BUILD-UP PART 4.
Added Comp Cams XE262H-10 "Xtreme Energy" hydraulic flat tappet cam. 218/224 dur @ 0.050, .462/.469 lift, 110 deg LS. Set initial timing to 16 deg BTDC.
270 HP @ 5,100 rpm. 291 ft/lb torque @ 3,800 rpm.
The cam change resulted in a huge increase of 53 HP. Torque was up by 6 ft/lbs.
305 BUILD-UP PART 5.
Replaced stock cylinder heads with World Products 305 S/R Torquer heads.
298 HP @ 5,500 rpm. 308 ft/lb torque @ 3,900 rpm.
A 28 HP increase over the stock heads, and the 305 engine now has close to 300 HP.
305 BUILD-UP PART 6.
Replaced World Products 305 S/R Torquer heads with '96 - '97 Chevy truck L31 Vortec cast iron heads, GM P/N 12558060. These are available from GM dealers in the USA for US $408 a pair, fully assembled. The Vortec heads require a different intake manifold, and Car Craft chose an Edelbrock Super Victor. They kept the same Holley 750 DP. Car Craft says that these heads are a bolt on for conventional small block Chevy engines. If your engine is earlier than '87, you will also need a set of self aligning rocker arms, and a pair of "center-bolt" valve covers.
325 HP @ 5,800 rpm. 317 ft/lb torque @ 4,800 rpm.
TECH COMMENTS
With peak torque at 4,800 rpm, the 325 HP 305 would definitely need some stiff rear end gears (I'd suggest a minimum of 3.7 ratio) plus a high stall converter if the car had auto trans. In my opinion the WP Torquer heads are the better choice for a street engine. I think that a 300HP 305 with 308 ft/lbs at 3,900 rpm, would be a nice street / strip combination.
(Built with simple bolt on mods!)
This information is a brief summary of an article that appeared in the March 1999 issue of Car Craft magazine.
If you are seriously interested in this build-up, I suggest that you find a copy of that issue.
305 BUILD-UP PART 1.
Car Craft started out with an 80,000 mile (130,000km) 305 LG4 engine from a 1982 Camaro. They removed the engine from the Camaro and put it straight on the dyno with headers, 3" dual pipes to Flowmaster mufflers, and a HEI distributor with 22 deg total advance. This gave a baseline dyno result of:
197 HP @ 4,000 rpm. 261 ft/lb torque @ 3,100 rpm.
305 BUILD-UP PART 2.
Added an Edelbrock Performer EGR intake manifold, but with the EGR blocked off.
217 HP @ 4,200 rpm. 285 ft/lb torque @ 3,300 rpm.
This is an increase of 20 HP and 24 ft/lbs over stock.
305 BUILD-UP PART 3.
Replaced Edelbrock Performer EGR intake with an Edelbrock Victor Jr single plane intake manifold. Replaced Q-Jet carb with a 750 Holley double pumper.
217 HP @ 4,200 rpm. 285 ft/lb torque @ 3,300 rpm.
This resulted in no change from the previous mods, maintaining the increase of 20 HP and 24 ft/lbs over stock.
305 BUILD-UP PART 4.
Added Comp Cams XE262H-10 "Xtreme Energy" hydraulic flat tappet cam. 218/224 dur @ 0.050, .462/.469 lift, 110 deg LS. Set initial timing to 16 deg BTDC.
270 HP @ 5,100 rpm. 291 ft/lb torque @ 3,800 rpm.
The cam change resulted in a huge increase of 53 HP. Torque was up by 6 ft/lbs.
305 BUILD-UP PART 5.
Replaced stock cylinder heads with World Products 305 S/R Torquer heads.
298 HP @ 5,500 rpm. 308 ft/lb torque @ 3,900 rpm.
A 28 HP increase over the stock heads, and the 305 engine now has close to 300 HP.
305 BUILD-UP PART 6.
Replaced World Products 305 S/R Torquer heads with '96 - '97 Chevy truck L31 Vortec cast iron heads, GM P/N 12558060. These are available from GM dealers in the USA for US $408 a pair, fully assembled. The Vortec heads require a different intake manifold, and Car Craft chose an Edelbrock Super Victor. They kept the same Holley 750 DP. Car Craft says that these heads are a bolt on for conventional small block Chevy engines. If your engine is earlier than '87, you will also need a set of self aligning rocker arms, and a pair of "center-bolt" valve covers.
325 HP @ 5,800 rpm. 317 ft/lb torque @ 4,800 rpm.
TECH COMMENTS
With peak torque at 4,800 rpm, the 325 HP 305 would definitely need some stiff rear end gears (I'd suggest a minimum of 3.7 ratio) plus a high stall converter if the car had auto trans. In my opinion the WP Torquer heads are the better choice for a street engine. I think that a 300HP 305 with 308 ft/lbs at 3,900 rpm, would be a nice street / strip combination.
