Burn the heretic - more changes from 'standard'
Discussion
I was keen to keep the Tuscan looking exactly like a Tuscan racer (allbeit without air filters sticking through the bonnet, and with rather better panel fit!).
But I was having big problems with side silencer basically burning up the car. I'd had to pull off quite a few track day laps and jump out fire extinguisher at the ready as the smoke/smell was so bad and I thought the thing might go up in smoke. I spent a fortune on heat control mat, reflective foils, and even got to the point of wrapping the whole silencer in exhaust wrap - but the problem wouldn't go. I know the racers don't [usually] go on fire, but maybe the Chevy on the carb just puts more fuel down the pipes, maybe the cam timing's different and there's more combusiton in the pipes, maybe just the 6.3 litres-worth is too much for the standard diameter pipes. Whatever, I was going to have to run with the silencer 'exposed'. But the standard box isn't exactly pretty....so I re-worked the look of the car slightly out of necessity.
Ooh...Ooh...there's more stuff about the new engine later in the post too
Now this little re-work was going to take a couple of weekends...and I ordered the silencers. Then the d@mn engine went pop again big time. We managed to save the block and the bottom-end, but the pistons and heads were lunched. Cue a rebuild
This time we kind of went to town on the breathing so it's now got Dart CC ported heads, a roller cam and lots of other wee tweaks. Bench dyno'd it still made pretty much the same peak power - near enough 500BHP...but whereas the last motor peaked at 5400 and the power really dropped off after that, the new motor holds its power well to 6500...in fact it's making 100BHP more at 6500 than the old motor, and that wasn't exactly short of puff.
Took a couple of months to get the engine ready - meanwhile I got the headers ceramic coated. Once the motor was back in the car I made up the exhaust system; now my stainless welding isn't great, but I guessed a couple of weekends welding, grinding and polishig. Jeez, how wrong was I Cut, weld, grind, leak test [filled pipes with water]. Dammit. Weld again, grind, test, dammit. Weld again, grind, test, dammit. Repeat for two and a half d@mned months of weekends 
Anyway, today I got it all fired up and went for a hurl - yes, it's dirty, but the roads are dirty. Jeeez this motor is fast
, spins up waaay quicker than the last one. And it pops and bangs like nothing I've ever heard on the overrun. It's embarrasingly loud 
. What the hell though.
Back on the road again
But I was having big problems with side silencer basically burning up the car. I'd had to pull off quite a few track day laps and jump out fire extinguisher at the ready as the smoke/smell was so bad and I thought the thing might go up in smoke. I spent a fortune on heat control mat, reflective foils, and even got to the point of wrapping the whole silencer in exhaust wrap - but the problem wouldn't go. I know the racers don't [usually] go on fire, but maybe the Chevy on the carb just puts more fuel down the pipes, maybe the cam timing's different and there's more combusiton in the pipes, maybe just the 6.3 litres-worth is too much for the standard diameter pipes. Whatever, I was going to have to run with the silencer 'exposed'. But the standard box isn't exactly pretty....so I re-worked the look of the car slightly out of necessity.
Ooh...Ooh...there's more stuff about the new engine later in the post too
Now this little re-work was going to take a couple of weekends...and I ordered the silencers. Then the d@mn engine went pop again big time. We managed to save the block and the bottom-end, but the pistons and heads were lunched. Cue a rebuild
This time we kind of went to town on the breathing so it's now got Dart CC ported heads, a roller cam and lots of other wee tweaks. Bench dyno'd it still made pretty much the same peak power - near enough 500BHP...but whereas the last motor peaked at 5400 and the power really dropped off after that, the new motor holds its power well to 6500...in fact it's making 100BHP more at 6500 than the old motor, and that wasn't exactly short of puff.
Took a couple of months to get the engine ready - meanwhile I got the headers ceramic coated. Once the motor was back in the car I made up the exhaust system; now my stainless welding isn't great, but I guessed a couple of weekends welding, grinding and polishig. Jeez, how wrong was I
Cut, weld, grind, leak test [filled pipes with water]. Dammit. Weld again, grind, test, dammit. Weld again, grind, test, dammit. Repeat for two and a half d@mned months of weekends Anyway, today I got it all fired up and went for a hurl - yes, it's dirty, but the roads are dirty. Jeeez this motor is fast
, spins up waaay quicker than the last one. And it pops and bangs like nothing I've ever heard on the overrun. It's embarrasingly loud . What the hell though.Back on the road again
Edited by tvrolet on Sunday 15th February 18:34
Nice job William...
I know what you saying about the stainless exhausts .. I'm having exactly the same issue.. except I'm using compressed air, some gaffer take and some chalk dust to find the leaks.. getting so fed up with it that I'm thinking of selling out and going and use a tig instead of my mig.
I know what you saying about the stainless exhausts .. I'm having exactly the same issue.. except I'm using compressed air, some gaffer take and some chalk dust to find the leaks.. getting so fed up with it that I'm thinking of selling out and going and use a tig instead of my mig.
get the tig rev , 
Willie - I think I can see brake dust on your wheels. You should be ashamed of yourself!!!
Nice work with the headers and exhaust system - looks really nice. It remains to be seen with our Chevy installation what happens with silencer box temps, having only tested in the dizzy temperatures of October! Quite what will happen in August we shall see.....
Nice work with the headers and exhaust system - looks really nice. It remains to be seen with our Chevy installation what happens with silencer box temps, having only tested in the dizzy temperatures of October! Quite what will happen in August we shall see.....
I showed a guy at work your pics, he's well into his Chevy V8's and he loved your car however he had this to say...
To get even more power and tone down the noise a bit, an expansion box with an internal crossover where the two chrome secondaries meet looks like a fairly straightforward packaging exercise. The expansion box would also help with the heat of the silencers. Chevy engines like an expansion chamber or crossover in that area, they don't run optimally with long secondaries and no crossover - quote Vizard.
Not a criticism, he may be wrong but thought I'd share just in case :-). Out of interest did you have a strong justification for going with equal length headers? Also is all that (inevitable) heat under the bonnet a problem on carbs? Looks like a work of art anyway.
To get even more power and tone down the noise a bit, an expansion box with an internal crossover where the two chrome secondaries meet looks like a fairly straightforward packaging exercise. The expansion box would also help with the heat of the silencers. Chevy engines like an expansion chamber or crossover in that area, they don't run optimally with long secondaries and no crossover - quote Vizard.
Not a criticism, he may be wrong but thought I'd share just in case :-). Out of interest did you have a strong justification for going with equal length headers? Also is all that (inevitable) heat under the bonnet a problem on carbs? Looks like a work of art anyway.
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