Hey guys!, I got a couple questions for my 91 Camaro RS if anyone is willing to answer/clarify




I'm in the process of building a Chevy 350 for my Camaro, which currently has a 3.1L in it, I've read the V6 to v8 sticky but there are a couple conflicts that has arose from either people saying otherwise, or research and numbers don't follow in line with the sticky.


First question: The Alternator and Power steering pump...the sticky says they cannot be used from the v6 what-so-ever, but according to my sources they should work just fine, I just need to get the v8 brackets from either a junkyard or online....is that true? or am I looking at new pump/alternator?


Second Question: Front suspension springs....I've read around on the forums and I have seen several times "upgrade the springs from the donor car" or "get the v8 springs".....when I looked up the part numbers via shopkeypro they are exactly the same, do I need to worry about the springs or are they truly different?


Third Question: Similar to the second, but with the brakes, people tell me if I'm going to put a bigger, more powerful motor into the car, I need to upgrade the brakes with the v8 version, obviously more power = more braking needed, when I compared the part numbers for the v6 and v8 (5.7, not 5.0) they are exactly the same.


Fourth Question: This isn't brought up in the sticky since it really only covers EFI swaps, the electric fuel pump....I'm going to be running a Multi-port injection setup using the HSR, will the fuel pump be able to handle the demand, or do I need to replace the fuel pump with the v8 version?


Fifth Question: Engine controls...The sticky says the ECU and wire harness cannot be used, from what I've gathered, it is possible, I know I have to at least splice in 2 more injector pigtails wired with their respective groups, my question is every other connection the same, TPS, O2S, IAC, ECT Knock, and I know I have to get the ECU reprogrammed which is no big deal, when I do get the ECU reprogrammed, is there a way to tune it via the ALDL? or do I need to pay someone to tune it...


And if there is anything else from the v6 that can be converted/swapped to the v8 I would like to know...less money for me to spend


Thank you for your time

 

Brakes are the same on v6 and v8 cars. Stock brakes on these cars are not the greatest so add more power now it's harder to stop, so brake upgrade is never a bad idea, but factory 6 and 8 cyl cars got the same brakes for the most part (some v8s got rear disk brakes as an option)

V6 springs will work just fine, ride height will be alittle lower if you use a full weight iron head/intake/water pump v8. You'll have about 1/2" drop/lower ride height

The V6 alt will not work with the v8 brackets as the mounting holes on alt is in a diff. location. (90* apart vs 180* apart)

 

that's what I thought with the springs/brakes, but I wanted it to be confirmed by someone who has done the swap, what about the electric pump?

 

Fuel pump for a carb, TBI and multiport all have different outputs. If you're switching from a V6 to V8 multiport then the pressure should be the same.

 

Yes, I'm swapping my Multi port v6 to a multiport v8

 

I'll try to stay in the order of the questions. Swapped my V6 for a carb'd V8 a few years ago.

1- the stock power steering pump should work, I'm pretty sure I'm still running mine. The alt I didn't reuse, but it's more because I changed to a totally different set of mounts that weren't used on thirdgens.

2- I did upgrade to the V8 springs when I did my swap, thinking the V6 springs would not handle the added weight of the V8. I'm running an old 70's iron block with iron heads(416's) and water pump. I too found a lot of conflicting part numbers and info on the front springs when looking and decided to go with V8 springs just to be safe.

3- I still have the stock front brakes on the car. I'll be replacing them with C4 front calipers soon though, probably next winter. I used the stock drum brake rear for a summer, until a posi disc rear showed up in the local junkyard the following spring(cash 4 clunkers 4thgen). I haven't really noticed any difference in braking with the stock front calipers. As mentioned above, the front brakes were the same on all cars, except the 1LE camaros.

4- the fuel pumps have different part numbers everywhere I have looked, so I'm guessing they are different. I'm not sure about the required pressure for V6 vs V8, but I thought the V6 was higher. I will say that I've had absolutely no issues running my stock V6 fuel pump with my V8, but I'm using an adjustable regulator to knock the pressure down to the 6 psi or so that my carb needs.

5- you can reuse all the sensors that I can think of. You mentioned splicing in 2 extra injector pigtails, which is correct. Since you'll need to reprogram the ECM anyhow, I don't see why you can't use the one you have now. Chevy used the same ECM in the V6 and V8 cars, just swapped in a different memcal. You may need to lengthen some wires though, like the TPS and IAC pigtails. The only other issue I can think of there, is if you use a MAF based system instead of MAP based. You'll need to add the wiring for the MAF sensor and it's relays.

As to programming the ECM via the ALDL, no. It doesn't work that way. With the stock ECM, you'll have to remove the memcal to burn a new tune to it.

You didn't mention it, but what are your plans for a transmission? Your V6 trans won't bolt up to a V8, the mounting bolt patterns are different.

 

I just finished my V6 to V8 swap a month ago, although I went to a carb setup its not that different.

 

i plan on rebuilding a v8 700R4 and replacing my v6 700r4

im going to keep it a speed density system

my Car is a 91 RS with the 3.1l, not the 2.8

 

There are differences year-to-year, as you might imagine. The sticky was written as a general guideline, so there are some things that may not be covered.

In my case, the '82 V6 car had a different PS pump than the '86 V8 donor car. Could be unique to the V-belt set-up, not sure if the difference carried over to the serpentine years.

As I understand, the MPFI pump pressure is fine for TPI, but it doesn't have the volume capacity for TPI. TBI pumps will not get the job done on TPI. Interestingly, a TPI pump will work fine with TBI or MPFI (but that's usually not the direction of swaps). Some parts places sold one pump, the TPI version, for all applications to simplify stocking.

The 3.1 V6 used the same radiator as 305s and 350s. #6 in the sticky. Not so with 2.8s.

Gauge sensors are probably not the same, but again, the devil is in the details. Most V6s, as I understand, used a 0-80 psi gauge, but V8s used a 0-60 psi unit, and the senders were different for the two ranges. But, you may be able to use the V6 sender with the V8 engine with the V6 oil pressure gauge (I did). That was several years ago, though, and I don't remember what application I had to cite in order to get the 0-80 psi sender. The temp gauge used a different size hole in V6s vs. V8s, as I recall (may be wrong there).

The V6 springs in a V8 swap is something that seems to have opinions both ways. I didn't change out the V6 springs, and with the V8 the car would bottom out constantly. I swapped over the V8 donor car front springs, no more problem. (I did use the V6 springs in another 3rd gen with a LS1/T56 swap, and they worked fine in that car). If you don't use AC with the V8, you can probably get by with V6 front springs.

Your fifth question is covered in #11 in the sticky. Again, specifics aren't offered, because of all of the possible combinations out there.

 

The 2.8L and 3.1L v6 listed weight is 350 lbs.
Iron head/intake carb'ed sbc listed at 575 lbs
Iron head/alum intake sbc is 540 lbs
Alum heads/intake sbc 495-505 lbs

So the extra weight of the V8 will not effect the the suspension/v6 springs