V8 Chevy Rebuild
Discussion
A follow up question. If I'm aiming for 250-300 hp what is my best carb option mindful that I need it to be as flat as possible? The carb that came with the engine is 110 mm tall, assuming I fit a pancake, which I would prefer to do, I guess it will add another 50mm. It would be ideal if I could find a carb/filter combination that would be around 125 mm. Any suggestions?
You’ll be best running a Holley double pumper. The other options won’t gain you height.
Manifold is where to look at for reducing overall height. To be honest with your desired power figures a lower dual plane manifold would be good.
A drop base air cleaner as fitted to some Corvettes is where you can gain more clearance.
Manifold is where to look at for reducing overall height. To be honest with your desired power figures a lower dual plane manifold would be good.
A drop base air cleaner as fitted to some Corvettes is where you can gain more clearance.
As already noted a drop base filter bottom suitable for a C3 Corvette will give the lowest filter option. Use a 'thinner' air filter element (so, 2" rather than 3" or higher). Using a K & N air filter top will give you far more additional air flow than any lost from using a 2" element. The only issue you may have with a drop base air filter bottom is the underside of the filter base interfering with the throttle cable routing and bracketing........might need to make something up yourself. Have you considered headers that face forwards instead?
This picture shows the engine as positioned by the previous owner, it was never run in this car. With the bonnet on the clearance to the carb is minimal. I have removed part of the rib from the bonnet underside, this has given me an extra 10mm. I can get the engine lower in this position and or get it lower and pull it forward so that the carb would be further from the scuttle panel and the chassis rail under the scuttle panel. The manifold, with is a Holley, seems to me to be pretty minimalist height wise.
I see that there are quite a few models of the Holley Double Pumper, any view on which would be best for my race application?
The idea of having the headers exit forward is one I thought about, indeed when I was at Brands recently I was looking at a car that had exactly that. In my case it would not work, the pinch point is the lack of width not so much the routing.
The advice is much appreciated.
I see that there are quite a few models of the Holley Double Pumper, any view on which would be best for my race application?
The idea of having the headers exit forward is one I thought about, indeed when I was at Brands recently I was looking at a car that had exactly that. In my case it would not work, the pinch point is the lack of width not so much the routing.
The advice is much appreciated.
Keep it stiff said:
I see that there are quite a few models of the Holley Double Pumper, any view on which would be best for my race application?
My guess (and it is a guess) would be something along the lines of this 650cfm DP with mech secondaries and man choke.?https://www.holley.com/products/fuel_systems/carbu...
Any part numbers on the intake manifold?
If height under bonnet is an issue, this Weiand intake is the shortest 4bbl intake available for a SBC, and showed good results in a spec engine test of 19 performance intakes for the SBC.
https://www.holley.com/products/engine/intake_mani...
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|https://thumbsnap.com/AbRizBva[/url]The horns that I have fitted are per your 2nd image , they were in a box of bits I got with the car. On both sides of the engine bay there is a 45 degree chassis box section. On the off-side, the steering column runs directly below this bit of the chassis and the 1st of two UJs is inline with the front end of the manifold. The existing UJ is a chunky thing that fouls however I will replace this with a less bulky UJ. On the nearside, to avoid the manifold clashing with the chassis I cut off the the brackets on the front of the manifold.
Manifolds wise I think I have two options, adapt what I have fitted or give them to someone as a template to make tubular versions within the approx. same dimensions. These pictures are a bit deceptive as the engine is propped on bits of wood given that I have not yet decided on the best position, also the steering column section is removed, they do however give the gist of what I'm working with. I'm not sure what sort of flex/twist to expect with the engine under load but my guess would be that I need to aim to be at least 20mm clear
I'm working away from home this week, I will have a hunt for those part numbers at the weekend.
Manifolds wise I think I have two options, adapt what I have fitted or give them to someone as a template to make tubular versions within the approx. same dimensions. These pictures are a bit deceptive as the engine is propped on bits of wood given that I have not yet decided on the best position, also the steering column section is removed, they do however give the gist of what I'm working with. I'm not sure what sort of flex/twist to expect with the engine under load but my guess would be that I need to aim to be at least 20mm clear
I'm working away from home this week, I will have a hunt for those part numbers at the weekend.
I might have missed it earlier-on in the thread......but what is the base vehicle (a 100E?) - on the subject of exhaust headers........no doubt you'll know that you could almost leave it to far later in the build-up and send the car to an exhaust specialist to have custom headers built-up for the car (once final engine location etc is determined........it's an expensive exercise though. I see your logic in trying to find cast headers first, excepting any potential power loss and perhaps upgrading to something more sophisticated later on............
roscobbc said:
I might have missed it earlier-on in the thread......but what is the base vehicle (a 100E?)
Its a Gilbern GT.Thread elsewhere on the car here https://www.pistonheads.com/gassing/topic.asp?h=0&...
Edited by aeropilot on Wednesday 2nd August 12:07
aeropilot said:
roscobbc said:
I might have missed it earlier-on in the thread......but what is the base vehicle (a 100E?)
Its a Gilbern GT.Thread elsewhere on the car here https://www.pistonheads.com/gassing/topic.asp?h=0&...
roscobbc said:
aeropilot said:
roscobbc said:
I might have missed it earlier-on in the thread......but what is the base vehicle (a 100E?)
Its a Gilbern GT.Thread elsewhere on the car here https://www.pistonheads.com/gassing/topic.asp?h=0&...
https://www.pistonheads.com/gassing/topic.asp?h=0&...
roscobbc said:
An interesting 'alternative' V8 build-up - love it!
Gilbern built 202 of the GT between '59 and 66. It started out with an A series engine, a few of which were supercharged, they then moved on to the B series and towards the end a few were built with Ford V4, with Ford becoming the base for the Genie and Invader models that followed late '60s and into the '70s. There was only one V8, built by the factory at the request of a local racer, Ken Wilson, this is the car I'm restoring. The club have membership records on approx.100 GTs so in % terms the survival rate has been high.I own another GT, a car I purchased in bits in 2019 and have been racing for the last few years'. This is a B series car, built in '64 and having built it to original specification I have FIA papers for it. Compared with MGBs, I run about mid-pack.
As a one off factory car there are few details on the V8, it is mentioned in several books, Autosport of the era and I have various race/sprint results from period. As a one-off it will never get FIA papers, there a couple of race series that it would sit well in and having spoken the organisers and their message is the same, in that providing I keep it in period and don't take the piss they will welcome it to the grid. So practically speaking this means I can upgrade for reliability, for example using electronic ignition, hi-torque starter etc. but not use fuel injection.
Ken Wilson owned a number of race cars, this was the era when ex team Jags, Astons, BRMs etc were sold from works teams and picked up by club racers who sprinted and raced them, now of course these are these are highly valued classics, Ken's Lister Jag, is a regular on the historic scene and if it came to the market would have a seven figure price tag. Coming back to the more modest Gilbern Chevy GT, it was reported that Ken borrowed the V8 for his boat which subsequently sank.
The body restoration on the Chevy GT is now complete, restored to Ken's original colours, red with a white bonnet stripe, and hence the next big task is to get the engine into position before I move on to other things. I will be racing it next year. Pictures bellow of the Chevy GT and my regular GT.
Edited by Keep it stiff on Thursday 3rd August 06:48
roscobbc said:
It would be interesting to understand what spec' the original Chevy engine was - perhaps which vehicle it originally came from. When people mention Gilbern's its always the later cars that seem to be mentioned.
I wouldn't be surprised that it came out of a early 60's or even late 50's Impala that was in one of the many East Anglian scrapyards from US serviceman leaving cars behind. A 220-230hp 4bbl PP 283 out of a 58-62 Impala would have been plenty of grunt for such a light car at the time.Gassing Station | Yank Motors | Top of Page | What's New | My Stuff