Low Budget 350 Chev - Page 4

Crankshaft Selection

A basic rule of thumb with engines is more cubes more horsepower. Before I started racing the Crisis Altered I had convinced myself the small cube 307 Chev was only "there" until I got used to driving the altered and worked out a bit in the area of tuning an alcohol (alky) engine using a carby not injection. I figured if I made a mistake and hurt the engine all would not be lost and I could confidently try things you would not do to a good engine.

I had envisaged building a stroker engine - 383 cube using a 3.75 stroke crank. A 383 would have made more than enough horsepower and torque for the Altered and it could have been driven all season without stressing components. An average street car driven by an under 25 year old would have had to cope with more of a flogging.

Right up to the point of deciding on pistons I had investigated the stroker crank and the only drawback for this budget engine was that the crank would have to be externally balanced unless I went to 6" conrods. This would have meant considerable extra money would have to be spent in getting the 6"rods, a new flexplate to suit a 400 cube Chev and a different harmonic balancer. In the US it would not seem that much of an expense but over here in Oz an average externally balanced flexplate is about $200 and a new harmonic balancer to suit (Fluidamper) $900. As there is not a lot of 400 Chev bits around my area second hand parts are rare so I would have had to buy new. A set of 6" H beam rods would have been cheaper to use the internal balance crank but the choice of "available" pistons was limited and they were twice the price. (Admittedly they were better quality)

So to keep the budgie engine on budget it was decided to go for the 350 cubes. I have a few cranks in my possession but mostly 307/327 both large and small journal, cast and forged, although I did have a 305 marine engine that I believe is a 350 crank that may be lightened to suit the smaller 305 pistons. Using this may have resulted in Mallory metal being needed in the balance and it costs around $100 a piece!

Maximum RPM is intended to be kept at 6500 to give the engine a longer life and I believe (hope) a cast crank would last in my case instead of a forged one. Remember the car is light and I intend loading the engine and putting as much torque to use to get the car hauling not high revs.

Now the sums, a second hand crank, freight to get it here, crack testing then regrinding all add up. The purchase of a brand new cast crank was considered excellent value for money. There are three brands of off the shelf crank available in Oz and they are all probably as good as each other for my intended use. Since I use the Internet to research most items of purchase, two companies had little or no information to be found and the other has a rather informative website that listed an e-mail address for tech questions, the choice was almost made for me without reading any specs. Hey how technical do you want to get for an el-cheapo crank. Anyhow I asked the question on availability (Australian Agents) and my e-mail was answered. I could not get the part number I had chosen and the only one available here was the standard drop in replacement so It was ordered. Apparently the crank ships balanced from the factory so you can drop it in a 350 Chevy, so I have since e-mailed the cranktech and asked the bobweight they use but to date this e-mail has not been answered. What these big companies don't realize (US Spelling) is that each and every genuine enquiry should be considered a potential sale and they also don't realise one sale may lead to many (word of mouth) and in this case how many potential customers around the world may be reading.

After receiving the crank and seeing the quality (remember it's only a cast crank - nothing exotic!) I was quite impressed and the final cost was not much more than a regrind. I would recommend one of these cranks to anyone building a basic Chev engine as they are really well finished. (What brand? - They aren't sponsoring me so I won't give them free advertising. :^) E-mail me if you want more info.

The next page in the buildup will jump out of order as while surfing the net I came across a new company I had never heard of who make manifolds. They looked good with a price that resembled value for money, so even though I didn't need an inlet manifold I splurged out and ordered one for the budgie. When it arrives I will post a review on the next page in the series..

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