I ran an old 72 318 short block with TRW 10.5 forged pistons. I got the short block fresh from my brother. I put the top end of my 68 318 on it, with the old cam from bro's 78 Lil Red Express (stock 340 cam) with Rhoades lifters and dropped it in my daily driver 68 Barracuda fastback. (I put this combo together for under $400 as a broke college kid).
It ran great with 24" vacuum at idle. My Barracuda had the "Performance Indicator" / vacuum gauge in it, so I used it to help my driving style.
During summer days over 80° F it would overheat after 20-30 minutes of running time. I asked my engines prof what the problem could be, and he said my compression was too high and we were getting a preignition. So I found a set of 77 360 heads locally with a fresh valve job for $150 and threw them in with a stock 68 340 intake and Holley 600 vac secondary carb. (I did have the stock 318 heads and 2 bbl on it originally).
My idle vacuum was not at 22 1/2" Hg, and it still ran real strong. No more overheating over 80° F and I could get 17.75 MPG on the highway with my stock 2.76 7 1/4" rear end. It wouldn't roast the tires, but still pulled strong on acceleration. It even impressed a cop once (but that's story I'd rather not get into)....
With the high intake vacuum, I was able to put a 10.5" power valve in my carb and was able to part throttle accelerate on the highway without getting into the power valve for better economy.
The next step up Lunati cam is getting close to the .500" lift range, which I feel is too much for a daily driver. It will have a faster valve speed and will beat the seat up faster than the 60401. It will also have less vacuum, so that is why I say to go with the 60401. The less lift will also give you better fuel economy. That's a good compromise for power and economy.
It ran great with 24" vacuum at idle. My Barracuda had the "Performance Indicator" / vacuum gauge in it, so I used it to help my driving style.
During summer days over 80° F it would overheat after 20-30 minutes of running time. I asked my engines prof what the problem could be, and he said my compression was too high and we were getting a preignition. So I found a set of 77 360 heads locally with a fresh valve job for $150 and threw them in with a stock 68 340 intake and Holley 600 vac secondary carb. (I did have the stock 318 heads and 2 bbl on it originally).
My idle vacuum was not at 22 1/2" Hg, and it still ran real strong. No more overheating over 80° F and I could get 17.75 MPG on the highway with my stock 2.76 7 1/4" rear end. It wouldn't roast the tires, but still pulled strong on acceleration. It even impressed a cop once (but that's story I'd rather not get into)....
With the high intake vacuum, I was able to put a 10.5" power valve in my carb and was able to part throttle accelerate on the highway without getting into the power valve for better economy.
The next step up Lunati cam is getting close to the .500" lift range, which I feel is too much for a daily driver. It will have a faster valve speed and will beat the seat up faster than the 60401. It will also have less vacuum, so that is why I say to go with the 60401. The less lift will also give you better fuel economy. That's a good compromise for power and economy.
