My L03 Plans & Some Questions

[DeuceRooster]

Pretty sure that's the pump I have on my '88 K1500 5.7L.

Excellent

Don't forget the modern, high-flow (honecomb, monolithic) catalyst.

Okay I will order one, my original pellet style is in terrible shape.

Asking for cooling system, alternator, and PS problems.

Hopefully not, I will keep a close eye on it though and if I have any of those issues I will swap the stock one back on.

NOTHING special about a 3-angle valve job.

GM never put 1.94 valves onto a 305. Far as I know, they never got anything bigger than 1.85.

When these heads were rebuilt the 1.85s were upsized to 1.94s which probably won't do any good. Likely will just hinder the flow due to how much shrouding they have now.

Thank you for your response.

 

[DeuceRooster]

For something you are just planning on messing around with the 305 can easily crank 250-275 HP and 300-330ish TQ at the crank with 081 heads and the little 1102 cam. They made 230 hp and 300 tq stock with the RPM challenged TPI, horrible factory tune, the restrictive OE log F-car manifolds and a tiny little 202/207 roller cam that only had 0.415/0.430 lift and was on a wide 117 LSA.

Years ago on a tight budget I had a 305 block built as a claimer bottom end. Flat top pistons, X rods, and some decent machine work done for a very good reasonable price. They built the short block and it was zero decked. I assembled it with a set of rebuilt 081s that had been surfaced and had a 3 angle valve job and good springs but otherwise stock. I used a replacement for the GM 929 camshaft. Same camshaft grind that came in 85% of the basic small blocks ever built including the TBI 350. I put it together with the stock TBI and TBI intake manifold and a set of 1.5" primary Flowtech long tubes into a dual 2.25 to single 3" exhaust. I had to do minimal tuning to the ECM and used 350 injectors in it. In summer heat it made 191 whp and 278 wtq on a Mustang dyno through a 700r4 and 8.5 10-bolt with a clutch fan on it. It also managed 17 mpg in mixed driving running around with the ac blasting with the 3.08 rear gear in a 5,300 lbs brick.

This is some great info. Especially knowing you did that on a stock TBI and stock TBI intake. I have read a lot of your past posts and took notes on everything. You have done a lot of trial and error scenarios which has helped for the future when I do eventually switch to a larger displacement.

 

[L31MaxExpress]

Excellent


Okay I will order one, my original pellet style is in terrible shape.



When these heads were rebuilt the 1.85s were upsized to 1.94s which probably won't do any good. Likely will just hinder the flow due to how much shrouding they have now.

Thank you for your response.

I always ran 1.94/1.60 valves in 305s that I setup to make good power. The valve is shrouded mostly by the chamber until ~0.450". 0.450" is where the valves drop below the chamber into the bore. A head porter worth their brass knows this and the chamber itself is a large part of the actual porting work. This is why Edelbrock used to say you could run their 2.02/1.60 valve heads on a bore smaller than 4.00 IF you did not exceed like 0.425" lift. Even if you took the same head and flowed it on a 4.155" bore plate the lower lift flow numbers under 0.500 are not changed much at all. The shop I had access to a flow bench on had a 3.905" bore plate, close enough for me. They also had a 4.030 and a 4.155. Notice those are 0.030 over 283/307, 302/327/350 and 400 bore sizes for a reason. Once you get to 0.600+ if the port can flow more airflow the larger bore easily pulls ahead, but the reality is most stock SBC head castings stop flowing by 0.530" and the difference between a 3.905" and 4.155" plate is minimal where the port stall happens. The stock 062 Mexican Vortec head port stall before 0.450" and actually decrease in flow over 0.450 as well. So there is much more to that whole picture. The larger valve has more curtain area and will generally flow more at low-mid lifts right where the cylinder head needs to work with a very mild cam profile.

 

[L31MaxExpress]

This is some great info. Especially knowing you did that on a stock TBI and stock TBI intake. I have read a lot of your past posts and took notes on everything. You have done a lot of trial and error scenarios which has helped for the future when I do eventually switch to a larger displacement.

I also took lessons learned from building that 312 back in the day and applied them to the 383 and to a lesser extent the 350 I just built as well. High compression, tight quench, fairly tight piston ring end gaps, great flowing heads, relatively mild roller cams, tri-y headers and EFI with computer controlled advance curves made all the difference. The 383 has less cam so it does not make the HP per cubic inch that the 312 did, BUT it was right there in torque. The 305 was cammed to make peak power at 6,500 and I wanted the 383 to hit peak around 5,500. Peak torque RPM thus was also close to 1,000 rpm sooner on the 383. My 383 would have to make about 520 hp to make the same power per inch the 312 made. Torque number was almost a direct scale up.

Power per $ spent you are always better off building as many cubes as you can. Looking back my 383 should have been a Dart SHP block 427 SBC. In the overall build it would not have cost all that much more.

 

[GoToGuy]

I didn't say it couldn't be done. I believe when you crunch the numbers , to get the torque and horsepower your targeted , that a $ 1000- budget would be a challenge to meet his expectations. You throw enough money at it you can get what want. A 1000$ does go as far as it did five years ago. The increase in inflation is proportional to the decrease in quality parts and such.
You have a plan that works , dive in , share what you learned. I love to hear of good news or good ideas.
Or even , hold my beer , watch, but don't this it hurts, a lot.

 

[L31MaxExpress]

I didn't say it couldn't be done. I believe when you crunch the numbers , to get the torque and horsepower your targeted , that a $ 1000- budget would be a challenge to meet his expectations. You throw enough money at it you can get what want. A 1000$ does go as far as it did five years ago. The increase in inflation is proportional to the decrease in quality parts and such.
You have a plan that works , dive in , share what you learned. I love to hear of good news or good ideas.
Or even , hold my beer , watch, but don't this it hurts, a lot.

To me it sounds like he is using mostly parts he has laying around to pep up an engine that could stand to have made more power stock.

 

[GoToGuy]

Got it. Understand that well. Before I went on overseas contract I loaded up my trailer and truck , went to. Bay Area swap meet. To shave down my 20 plus years of parts. My young brother along as helper. I priced things to move but not give away. Everything single item except the lake wood blow proof bell housing sold. I paid my brother in law 200$ for helping. After big lunch, gas, entry fee, I drove home with $6200. " Here take my money, now." Guess I had more stuff than I thought..

 

[Bondovw]

Don't forget to use zinc with that cam for break in.

 

[Schurkey]

Don't forget to use zinc with that cam for break in.

Ehhh. If you need additives in your oil, you've probably selected the wrong oil.