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305 is a boat anchor looking for a tramp steamer to claim it. Bores are way too small to make any power. You need a minimum of a four inch bore block (327 or a 350) that you then rebuild as a 383. Or find a SBC 400 and rebuild it as a 406 (standard rebuild) or a 424 to a 454 (which is much more expensive depending upon the displacement and parts being available from China).

At least with the 305 motor you have an 8.5 inch corporate rear that can be built up to handle a 406 easily.

Big Dave
 

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A 350 can be a high reving 355 for the strip or a 383 stump puller for the street. 1969 means it is a good candidate as it will have a stronger block (newer engines have a weaker block as Chevy pulled out cast iron to save money knowing a smog motor wouldn't stress the block, and to lighten the block to improve CAFE numbers for federal reporting).

Big Dave
 

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A 350 can be a high reving 355 for the strip or a 383 stump puller for the street. 1969 means it is a good candidate as it will have a stronger block (newer engines have a weaker block as Chevy pulled out cast iron to save money knowing a smog motor wouldn't stress the block, and to lighten the block to improve CAFE numbers for federal reporting).

Big Dave
What he said..
 

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You can expect 140 (2 barrel base engine) to 350 horsepower in the Z/28 and LT-1 Corvette with factory heads (three different choices in intake port size and vale diameter). You also have to consider induction (carb cfm, and intake manifold). Almost all SBC engines had had the same log cast iron exhaust manifolds. Bigger pipes and dual exhaust disappeared after 1974.

Need to add to what Art said to include compression ratio. 1970 was the last year for a performance engine (the 350 horse 350 in the Camaro, Nova, and Corvette). 1971 was the beginning of the end as compression dropped in anticipation of unleaded gas that was supposed to appear at your local gas station in 1974. It fact wasn't fully implemented until 1983 when the last of the leaded gas disappeared, so we lost a full decade of muscle cars to a policy that wasn't followed.

With today's pump gas being the same octane rating as was used in the late fifties you are limited in your compression which is free horsepower. With a 350 equipped with modern aftermarket heads, and a modern computer designed roller cam you can obtain the 500 horsepower numbers that are common today. You will never see more than 350 out of a factory casting even with porting and bigger valves as they are restrictive compared to today's free flowing heads, and today's gas will not run in a 11.5:1 engine.

By the way get horsepower out of your mind unless you are going for a land speed record at Bonneville or are chasing your tail around the high banked oval track of Daytona or Talladega. Those are the only form of racing where horsepower matters (and used to be painted on the hood of the cars back when they actually ran a modified stock car at the race track).

What you want to think about is building torque. The more torque you can generate the faster you can accelerate your car's weight. That is why I mentioned the 383 option since it has a longer stroke than the 350 and can more easily generate more bottom end torque. It is also why you won't find a 4x4 diesel truck at the race track, with a 1,000 foot pounds of torque from idle to WOT they have a distinct advantage over a gas engine, and are banned by the NHRA from racing (they have their own tracks for drag racing and pulling semi trailers).

Big Dave
 

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Yeah, start with a 355 built to '70 LT1 specs...tickle it with a 150HP whiff of nitrous...then you're ready for Street Outlaws. ;)

Elvis

P.S. Weren't we talkin' about inline sixes? Whatever happened with that kid?
 

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You just use the normal hot rod tricks on it And with to days tech you can even go to fuel injection .I have even seen people split the exhuast .There should be some books out there from SA and HP books that may help.
 

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Discussion Starter · #37 ·
Ok I wanna tubocharge the in-line six any suggestions on what I should go with? And replaced the muffler now it has a growl and I like it thank you Elvis.
 

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Take the muffler off all together. The turbo will be your muffler

Install twin turbo(s) off of two Plymouth or Dodge Neons (K-cars). You have 4.0 liters of engine to feed and the Neon has a turbocharged 2.0 liter four cylinder engine.

Use everything in terms of plumbing as you can hit (waste gates, inter cooler tubes intercoolers, oil feed lines, everything that isn't a four cylinder engine.

You will have to fabricate your own custom tubular headers feeding the two turbos with three cylinders each powering a single turbo. This limits lag time to spool up and will power your car with four to six psi of boost. You will also need to go to port injection EFI with two longer duty cycle injectors on the two middle ports (that feed two cylinders) and two shorter injector cycles (fewer pounds of fuel per hour) on the end ports.

If you ever get it running don't forget the race gas as your going to be adding a lot of dynamic compression. Just keep track of expenses and compare it to a 305 SBC out of a high mile Chevy in comparison to cost. Both will have the same power level. If you want more power out of a turbo charged six you need SBC Siamesed heads welded together to make a six cylinder in-line head a new cam, and forged pistons with deep dishes to keep the dynamic compression pressure down to be able to burn gasoline: or you could burn straight methanol like an F1 race car.

The only down side to a Chevy straight six is it will crack the block between the #1 cylinder head bolt and the water outlet bolt every time it is pushed hard. So you will get good at engine building after a while. I got to where I could pull my burnt up VW engine out of my Karmen-Giha and rebuild it on my lunch hour I did it so often. Six is more cumbersome and a lot heavier (I could yank the mostly magnesium VW engine with one hand and carry it to the work bench)

Big Dave
 

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You may want to install an high-flow cat-back exhaust system, you can find a wide variety of options all over the internet. My favorite brand is Magnaflow, been using the pipe for 5 years now and whenever I encounter a vibration problem I just simply tighten it.
 
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