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Porsche 914 V8 Engine Transplant Feature

by | Apr 15, 2010 | Classic Porsche Blog, Modified Porsche Hot Rods

This pretty little Porsche might look like a factory hot rod, but it hides a guilty secret. John Glynn went to California to find out more.

Engine transplants have been the backbone of hot rodding since Moses was a boy. Nothing is more renegade than running an excessive engine in a chassis that was never designed to handle tons of torque. Overdosing on power-to-weight, and then making that package work is what custom car construction is all about.

When Bob Marx took the temporary motor from his 454 Chevrolet Chevelle SS, to refit the rebuilt original powerplant, he was gifted a great-running V8 with nowhere to go. Later that week, while cruising a friend’s E36 BMW M3 Cabriolet down to a Silicon Valley car show, the thought occurred that building an open-topped European vehicle with all-American power might be kind of fun.

Spotting a Porsche 914 at the show, Marx took a closer look at the engine bay. He was convinced that the spare V8 would fit in the mid-engined location. The hunt began, almost immediately uncovering this car just a few miles from Bob’s home in Pleasant Hill, on the outskirts of San Francisco.

Marx’s machine began life as a 1700cc 1972 914.“A rust-free California car was what I was looking for,” recalls Bob, “and the owner assured me it was exactly that, so I went and had a quick look. I noticed a few things I didn’t like, but we agreed a deal and I brought it home to get to work. As I began stripping back to the bare tub, I uncovered more and more rust, along with some shocking hack jobs on things like the wiring. It was not the best of starts.”

Although classic Teener rot spots, such as the hell hole (the area under the battery tray), front floorpan and rear luggage space needed nothing bar a quick wire brushing, extensive corrosion was uncovered in the sills, floorpans and battery tray. Bob cut out the rust and welded in new repair panels, before taking the exterior down to bare metal and welding on the steel GT arch pack, key to the look of this car.

Sold new with mid-mounted 1.7 or 2.0 litre engines, cooking versions of the 914 were never intended to take the power of a small-block Chevy motor. Strengthening the chassis was essential to deliver a safe, confident drive. To achieve this, Bob welded in the longitudinal and rear arch stiffening kits, to minimise rear flex under power, which would ultimately have cracked the back end. He also ensured that the factory stiffening was still working as it should.

Porsche had only ever fitted air-cooled engines, so work was needed to house the water cooling required by the incoming Chevy. A custom rad was fitted in the nose, with homemade ducting to direct cold air through it. Lightweight Gates hoses carry coolant back and forth. The front valance was modified to let the air in and then painted satin black. At the back, a bi-folding engine grille was built, again for better airflow. Both look great. The reflection of the grille in the rear glass, set between the side buttresses, is a really sweet aspect.

With the chassis work now just about complete, Bob sent his wide-arched shell off to be blasted with baking soda. Once this was done, the attractive bare-metal bodywork was returned to Bob’s workshop, for final parts fit before the whole thing was painted in Porsche Guards Red. The colour looks perfect in this California light: not too brash and not too boring.

The engine is a 1968 327 cubic inch V8, built in Detroit and originally fitted to a Corvette. 327 cubic inches is 5.4 litres: over three times the size of the original. Prior to installation, Bob rebuilt the motor with some trick parts. The block received a light hone before Keith Black 10:1 pistons were slid into the bores. An Edelbrock intake manifold, topped with a 610 cfm carburettor from the same manufacturer was securely fastened to the top end.  Stock Chevy headers flow into sexy, GT40-style exhaust pipes. Power is an (under)estimated 345 bhp.

The 901 gearbox is a Porsche classic. Though never built with 350 bhp in mind, it’s a strong, reliable unit which, driven considerately, is nicely suited to the lazy torque of a big V8. The 901 is often seen in historic 911 rally cars, and normally requires no more than a strengthened sideplate and new crown wheel and pinion to make it bulletproof. But that’s with a hundred fewer horses stampeding their way through the transmission. Though this application is more car show and less Tour de Corse, it’s still a big ask.

The 901’s weak point is the dog-leg first gear, located left and back on the shifter. Too much power can twist the separate first gear shaft away from the rest of the internals, so Bob uses the engine’s humungous torque to pull away in second. I do the same in my 911s – it’s no big deal. Thanks to a parts wait, the tail shift mechanism is still fitted to the transmission. Meanwhile, Bob has switched to the slicker side-shift setup, to get the best out of swapping ratios. Future plans feature a more robust 911 Turbo transmission install.

Stance is everything on a hot rod and this one hits the spot. Sports cars sold in the USA have long suffered from vertigo, induced by the towering statutory ride heights that resulted from Ralph Nader’s safety campaigns of the 1960s. Returning the car to European ride height is a popular mod amongst US Porschers.

Tuning the suspension of a chassis that’s had its power tripled overnight is a tricky business, but Bob reckons he’s got things under control. Considering the stock front anti roll bar is thinner than an anorexic stick insect, and there’s no bar fitted to the rear, this sounds hard to believe, but it all looks flat as we follow the car to our photo location. The front is held up by torsion bars and controlled by Bilstein Sport dampers, with Bilstein coilovers and 200 lb springs at the rear.

Hiding behind those 7 and 8” replica Fuchs rims, wrapped in 225 and 245 Fusion ZR1 rubber, are front brakes from a 911 SC, and stock rears. Doesn’t sound like much with the power that’s on tap, but then this car is light, and the brakes have been fully refurbished with a new master cylinder, flexible hoses, caliper seals and the rest. The suspension has also been overhauled, with new bushes and joints all round.

Inside, the classic Porsche-designed cockpit has been left alone, with a three-spoke steering wheel and supplementary gauges the only new additions. Sitting into the car for the first time, I strap the harness tight and brace myself for action; this could be quite a ride.

Turning the key is cause for celebration. The Chevy cranks quickly into life and settles into that classic V8 fast/slow/fast tickover rhythm, which adds a dash of urgency to the low-slung seats and go-faster view along the sleek bonnet. I’m properly excited and we haven’t moved yet. Slipping the lever forward into second, I add a drop of gas and let out the clutch. The car slips from the kerb in a civilised fashion, encouraging me to try another gear.

Rolling on an ocean of torque, the Teener pulls effortlessly; normal speeds in third are a whole heap of fun. As we hit a stretch of smooth dual carriageway, I throw open the throttle and let the V8 sing. The Fabulous Fourteen unleashes like a cartoon Roadrunner, pouring hyperspace between us and the cars behind. This thing is more addictive than chocolate-covered coffee beans.

The direct gearshift and dependable brakes work well together. Thanks to the wider track, the steering feels fantastic. Although the front end ride is perhaps a little stiffer than I would prefer over rough roads, it’s early days for this car’s development: Bob’s only recently got it fully on the road. At the minute, he is concentrating on maximising the miles and just driving. Can’t say I blame him; it’s a wicked little grin machine.

A few days after we arrive back in the UK, I get an email from Bob about the car’s first show appearance. It’s gone down well, with lots of positive comments and face-wide smiles from those who don’t initially spot the V8 in the back. It’s all the validation needed to justify the blood, sweat and tears that went into making it.

My hat comes off to guys like Bob, who can take a concept, add weeks of work and almost single-handedly see it through to completion. This sweet little missile strikes a direct hit for men in sheds everywhere.


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