The Woofwagon. Beginning pictures

[justcuz]

Up I agree with the above comments. Bigger cubic inch engines can handle higher lift and duration. If you already have the #3 Caddy cam call those guys and ask them how it runs with TBI. I would say a carbed cam with 112 degree lobe separation and no more than 215 degrees duration at 050 would work fine on a 500 cubic inch engine. Harrison Performance/TBIchips.com has cam recommendations for a 350 on his website and you could e-mail him with your proposed engine build and see what he recommends.
Flat tappet cams should run less lift than roller cams because of the length and shape of the lobes (egg vs. grape) to reduce overlap and maintain sufficient manifold vacuum.
I have a cam in a TBI 350 that runs .420 lift on the exhaust side and a factory flat tappet 305 HO cam was about .403/.415 intake and exhaust lift @ .050. They used the same cam in a 350 Corvette in around 1978. Of course bigger engines can tolerate more lift, just keep the duration shorter to prevent overlap.
There are ways to convert your HEI to computer controlled distributor, I posted a vendor who does it in one of my previous threads. You can do an Internet search on converting your distributor and find tons of info. A stock TBI distributor is a small cap with no vacuum advance and an external coil. Changing shafts and bodies is doable but I think a conversion may be possible with your HEI or maybe an old point distributor.
Look were your knock sensor is now, I believe it is threaded into the block between the starter and the engine mount. Any thread holes in the side of the Caddy block that match the threads on the threads on the knock sensor will work. A knock sensor is just a microphone that listens for pre-ignition knock and retards the timing. It can be mounted anywhere, but along the side of the block is a preferred spot because it is closer to the cylinders.

 

[superbuickguy]

just don't deadhead the system and you'll be golden. you know, the offer still stands that if you want a hand with that - just give me a call.... by then I should have my FJ40 all dialed in.... this one

 

[Woofwagon]

Thanks for the offer on the help! I will definitely take you up on that. The engine still needs to be assembled. I need to inspect the bores for size to determine if a re bore is required (which I doubt). I will certainly keep you all updated on the progress.

 

[superbuickguy]

btw... that's the FJ40 you saw when you picked up the motor... it's had a few changes

 

[Woofwagon]

Incredible work! Wish I had a shop with a hoist like that! Currently, I'm saving up enough money to have the block thoroughly cleaned, inspected and magnafluxed. I'm considering taking the short block down there to have it inspected and then we can figure out what parts are going to need replacing besides wear items like bearings. I will pull the cam and lifters out this week. I have a new timing set, push rods, gasket set, front cover, cylinder heads, etc. I now need an Edelbrock Cadillac intake for it. I had thought about using the stock manifold but it is a negative rise unit and extremely heavy, probably at least 90+ pounds. With an aluminum intake, the Caddy will weigh just a little more than a SBC.

 

[chilliwak]

Looks like you are getting a lot of sound advice here Mr Woof. Glad to hear about your progression with your rig and like I said before I am looking forward to seeing the goodies mounted and ready to run. I personally love quadrajets and have basically good experience with them. I like the idea of having small golf ball size venturies/openings to run on while you give it a little gas and those huge grapefruit size secondaries for when you need that extra punch. I usually run a inline fuel filter before tha carb that can be replaced easily to take most of the garbage out of the fuel before it enters the carb fuel filter that can make for some vacum lock problems when they are replaced. I am an old school guy that once had to road fix some linkage that fell of while wheeling in the bush. I just dont have the satelite telephone and airlift capabilities with a crew waiting to fly in with a replacement computer when I am 200 miles from the nearest paved road. Ya, I guess I am really old school... Cheers, Chilli...

 

[superbuickguy]

I love q-jets, but give me a GM TBI system and I'll throw the q-jet in the corner. 20 years ago, I said the same thing, but the systems are light-years better now then when they started 40 years ago... yeah, 40 years. Where the q-jet can last up to about 100k miles, TBI just go until the truck dies - 200k, 300k miles no problem... yes, you can lose a fuel pump, but even that can be mitigated. On top of that, the efi never needs tuning for altitude and nets 2-3 mpg better economy. Factor that over a couple hundred thousand miles and the difference is pretty remarkable.

On top of that, the last half-dozen trips into the hills for wheeling have netted us zero EFI problems and 6 carb problems. One was so bad that we had to pull him home... I think you have to know how to tune a carb to get the most out of EFI; but on all levels, the efi is better - including longevity because of fuel-washing issues that are far more likely in a carb then a TBI.

Woof - it's funny about the FJ40, it gets resounding silence when blogged here. Where IH8Mud has 50,000 views, here... crickets...

 

[drewactual]

you can do things with EFI that is amazing, that you just can't do with carbs... I'm not a huge fan of TBI, but EFI I am... it took forever for it to take root, but it's undeniable.

one of my favorite tricks using EFI systems is fuel sync- most EFI systems fire the injector just prior to the valve opening, which cools and cleans the valve, while relying on the back of a hot valve to atomize the fuel better... with new injectors, the spray is finely atomized when it comes out- so, no need for that valve action... which means you can retard the timing about three degrees to increase power minutely but to increase fuel economy quiet a bit. Like, 2 full MPG's in some cases. Throttle response increases, too. The duty cycle can be trimmed to support this as well... I did this the first time on an old dodge 360, where I was having fuel trim issues.. I expected some gain, but was totally amazed when my STFT (short, not long) started crossing zero almost in a rhythm, as opposed to just at extended idle... of course my LTFT followed suit, and gave me almost a perfect reading in most every condition... I was impressed, and share this little trick as often as I can.

 

[superbuickguy]

TBI is certainly a limited-useful EFI; but on a nearly-stock 350, it's so reliable that it's pretty hard not to like it. With that said, my shelf contains a megasquirt 3x, and a Holley commander 950. I went with the TBI because on my nearly-stock FJ40, I'd be driving nails with a sledgehammer. However, on my twin-turbo, 455 Buick... it's just what the doctor ordered.

 

[Woofwagon]

Well with these experiences, it's sounding more and more that I need to go with either the TBI or a comparible EFI system. The TBI would be a whole lot cheaper to setup, but the tuning capability of the EFI is massive to say the least. TBI parts are still very cheap in terms of fuel injectors.

A stump simple and reliable system is what I'm looking for. I've already put out some feelers for a 454 TBI computer and injector body.

 

[superbuickguy]

Find a BBC system, even better a 502 BBC system and there will be no tuning, simply wiring. One of those "really cool things" about a 500 Cadillac is the interchangeability of the distributor cap between it and the Chevy V8s. Why is that cool, here's why - remember when I said you could simply put a cadillac base on a small, late model top? because the degree between firing is the same across the GM brands, its electronic spark control can be easily used as well. literally the 502 BBC spark and fuel systems can be bolted (with machine-work on the distributor, obviously) onto your Cadillac motor.... with no tuning needed at all. The cam you're picking is mild enough that it won't screw the computer up - while it wouldn't be optimized; it'd certainly be more then adequate to run your vehicle and get you better economy then a carb (not to mention the ability to run crap gas or tow huge loads over mountain passes).

Your job is to shop ebay until you find a complete, 502 TBI system with computer, harness FUEL PUMP, and distributor. Honestly, it shouldn't cost more then a couple hundred. Bonus points if you get the fuel pump and tank from an 87-91 'burb

 

[Woofwagon]

Awesome information. This helps me a great deal on what parts to find for this build. As I already have most of the TBI wiring in place for the 350, it should be plug and play as you have previously suggested.

 

[justcuz]

I think you may be right. Using the 350 sensors on the Caddy engine and just have the chip reprogrammed to accommodate the 500 cubic inches. The ECM does not know the difference between the Chevy or Caddy engine, they are both V8s. Just need to adjust the chip for fuel requirements to accommodate the extra cubic inches.

 

[Woofwagon]

I believe I found a complete TBI setup for a 454 on eBay. Complete wiring harness, computer and throttle body. The injectors may be shot, but those are really cheap to replace. What would be needed is an adapter between the throttle body and the Edelbrock manifold I want to use.

 

[justcuz]

There is a 454 TBI and spacer on eBay right now for $149.00 in Florence, Texas. There are also a couple of aftermarket adapters available in the $50.00 price range.