I have a complete LS1 with intake injection PCM harness all that stuff but im thinking it may be cheaper to switch it to carb...... also i might think about selling it and making the switch to 6.0/408 and big carb is there really any benefit to keeping the EFI for a non daily driver...... BTW this is going into a 70 nova

 

switch it to a carb its cheaper in the long run if u want tot do any kind of tuning with it. also it looks better putting these motors in an old car with a carburator in IMO. the carb setup is 600$ and you can get some money back after u get rid of all the EFI stuff. good luck!!

 

Carb the world, thats what i say, LOL.

Cheaper and makes more peak power. The only draw back is the EFI gets better MPG and you can finer tune it with a stock PCM, otherwise, you need a wide band on the carb car to get as close, no biggie.

 

Carb for sure.

 

thanks guys.

fastdriver at quick glance your car looks like my old one.....



here is the new one

 

If you already have all the FI stuff then I don't really see how it will be cheaper to switch to carb. To go EFI on an older car you will need a new pump and preferably a sumped tank. But if the old motor had mechanical pump then you may need the electric pump anyway, and a sumped tank isn’t absolutely needed. Going carb means sourcing an intake and MSD box. Not exactly a common item at your local swap meet, so it is going to be some money to buy new. Carbs you can get used cheaply enough.

I don’t know that tuning a carb is cheaper if you are starting from scratch. Carb tuning parts add up if you don’t already have a supply. Once you have them they can be reused, but the initial set up does add up.

To tune EFI right you really want your own tuning software, but IMO to tune a carb right you will want some sort of wideband. Sort of a wash assuming you have access to a computer.

So you tell us, what do already have and what are you going to need to buy?

As for carb vs. EFI on a weekend machine it almost doesn’t matter. Carbs don’t start as easily in cold weather and your motor won’t live as long as an EFI car, but for a weekend machine that is not a big problem. Once warmed up they both drive fine. I don’t agree with the better MPG out of one vs. the other. Most head to head comparisons I have read seem to be a wash.

Keep in mind all of this from a guy with a carb’d conversion.

 

well I have changed whats going on a bit the LS1 with the EFI and 4L60E is going into dads car i was going to build it but if i do that then i need a way to tune 1200.00 a pump as my car is a 70 nova injectors 400 intake sicne the stock LS1 intake was not going to to what i wanted......... so for what i want and have carb is going to be the best bet.... also it is not a DD it is a weekend hot rod racer. for dads build stock ls more DD style turn key and go.

 

No way around it man, the cost of a PROFESSIONAL dyno tune at a high end reputable shop is usually 500$, that nearly covers the intake and MSD box. The rest is cheap ****, like a carb and fuel pump, that is stuff you can cheap out on and it will still be reliable.

 

Its Kinda a Wash, my set-up is mostly used parts so I came out on the cheaper end, alot of efi stuff would make me less trusty on the used end except for intake, Throttle body

 

ok the combo that i have sitting here now (since i sold my LS1 to may dad) is a 6.0 iron block that is going to get new parts installed......

do I

1 use the stock crank good rods and pistons 243 heads CNC ported by wegner automotive
2 make it a 408 with 243 heads CNC ported by wegner automotive
3 make it a 408 with L92 heads CNC ported by wegner automotive

I'm looking for a bad street unit.... the car is a 70 nova show above with 3.25 gears TH400 28in tall tires and it will see the strip a few times a year.

 

11.5-12:1 scr 408 with worked 243 and aggressive cam and super victor intake

 

Nice Nova! You have a PM.

 

best bang for the buck is to leave it a 6.0, and just toss a cam/valvesprings/intake on it. which parts depends on how you want it to perform.
I notice you have 3.25 gears, do you plan to change them?

 

A built 408 will surely last linger, and be able to spray more if the want/need ever came, but they budget is just the issue, i would do a 427 from the 6.0 if i was to stroke it up. But for a street cruiser with the fun factor, a 6.o with cam and heads is just right keeping the pocket less abused.

 

it will have a bottle I think since i already have a wilson nitrous proflow direct port kit. that is the reason for the rods and pistons if i stay with a 6.0

No i don't plan on changing the gear it is a street car and i cruise longish trips on the interstate so i need some gear in it.

So my thought is the 408 with wegner CNC ported 243 heads will make the most average power and make plenty of peak to have fun. I know those heads on a stock 5.7 make 575CHP and on a stock 6.0 bottom end make 605 crank HP i have seen the dyno sheets for that so on a 408 it should be a realy street monster and if that is not enough then the 150 or 200 will get the job done if need be......

you can fit a big enough stroke in a 6.0 to go 427? is there really any cost difference to do that? will the compression height on the pistons give troubles for nitrous?

 

Cost is about the same, the 408 is a 4 inch stroke, the 427 is a 4.100, no biggie and it is worth 30 or so more HP.

 

How far can you bore a 6.0 block? i see a 421 kit from eagle it has a 4.030 bore 4.125 stroke. does that long stroke fit in a stock block? what about piston side load on a stock block? and piston speed?

 

Dont know how far they can be bored, but .030 i no issue, i know that a 427 stroker with the 4.100 stroke is becoming a common thing. Who cares about piston speed, as long as the pistons are forged, big block chevys have allot more stroke, larger pistons and rods and they dont have issues so i know a LS motor wont have a problem.

 

who makes a 4.100 stroke? i have seen the eagle kit with the 4.125.

BBC has a 9.8 deck height (or 10.2 for tall decks) so they can fit a longer stroke with out rod angularity issues....

 

Saw them on Ebay and there are sponsors here that sell the short blocks and i am sure there are some that sell the kits and cranks.