Looking for some input/advice

[Mike P]

Hi Dustin, welcome to the forum. Just a few thoughts from an old guy.


Being in that part of the country, I would defiantly go over the car with a fine tooth comb for rust issues, especially in the frame and suspension areas. It will be money/time well spent to get the car in the air (up on a lift would be ideal) and go over every inch of the frame and floor to make sure you have a solid car to start with. Even spending $50-100 to get it into a shop for an inspection is going to be well worth the money. Frame repair/replacement, installing new floors or exterior sheetmetal can quickly turn one of these from a fun project into nothing more than an expensive parts car. There has been more than one member who has found himself in that boat.

The second thing would be the engine swap itself. A SBC swap in one of these should be bolt in....if all the right parts are used. Unfortunately I have personally seen way too many that were hack jobs, forcing things to fit, butchered wiring, destroying the AC system and cutting corners (like neglecting front springs and cooling system). Pay careful attention to the engine and transmission mounting.

I think the seller is being VERY optimistic on this 450HP claim, I see nothing in that build that will come even close to that number.

As far as the belt setup.....personally I think it’s a matter of preference and what is visually appealing to the owner. Either has advantages and drawbacks.

As far as the rear end chances are the 7.5 will do fine for a long time as long as it’s in decent shape to begin with as long as you keep the tire size and driving reasonable. Options on upgrading the rear include:

An 8.5 from a turbo G Body or 442 (They usually run in the $600 and up area)

A 12 bolt from an A body ($500-1000 and up plus you will need custom upper control arms and may need different offset wheels).

9” Ford (usually $2000 and up by the time you pay shipping and get everything to get it in).

There is not really a cheap upgrade for the rear end, but some are more reasonable than others, and you never know when you will run into a “deal”.

Good luck, and like I said, check everything well.

 

[WiCK3D_SiX]

I got a bit ahead of myself listing mods. He installed the v8 suspension and has an aftermarket radiator, also a 2500 stall converter. True dual exhaust, and Flowmaster muffler's. Thanks for all the great info and advice.

 

[WiCK3D_SiX]

Also, how much power would you expect the set up to make? Closer to 300hp? He said its a small 303 lift cam with 10.1:1 compression.

 

[Mike P]

“.....Also, how much power would you expect the set up to make? Closer to 300hp? He said its a small 303 lift cam with 10.1:1 compression.....”


Really impossible to say with the information you have. The “303 lift” sounds way off .....even the small “RV” style cams are over .400 and a mild cam for a SBC is in the .480 range.

The Scorpion manifold is an old design and really doesn’t start making power until at least 2500 RPM. Chances are it was something that was either sitting on his shelf or a $50 swap meet item.



As long as I mentioned checking everything.......

Is the short block really “new” (as in factory crate SB) or a cheap box store rebuild? For that matter does it really have bow tie heads or just some plain factory castings? At least take a flashlight with you and look at the back of the block (where it extends past the driver’s side) there should be a casting number there. If it happens to be 5.0LG it’s a 305 not a 350......you’d be surprised how many “350” G bodies turn out to be 305s.

I know I can sound a bit cynical, but I’ve been around this stuff for a long time and seen a lot of cars/engines that are not quite as advertised when you get into them.

 

[WiCK3D_SiX]

trust me I know where your coming from. I planned on running any casting numbers I could find on the block and heads to verify parts.

 

[dogsht]

Mikes advice is spot on.

 

[85cut420]

What year is your Tahoe, and what is the mileage? If the deal seems too good to be true, it most likely is. If I put all that time and money into a car, I would definitely NOT give it away or trade for a vehicle of lesser value. Meaning that if your Tahoe is over 10 years old and/or has over 150K, unless it has candy paint, 26s, and dead-waking beat, I'd be wary of trading it for a car that is as nice as you described.

 

[jdracer13]

“.....Also, how much power would you expect the set up to make? Closer to 300hp? He said its a small 303 lift cam with 10.1:1 compression.....”

Is the short block really “new” (as in factory crate SB) or a cheap box store rebuild? For that matter does it really have bowtie heads or just some plain factory castings? At least take a flashlight with you and look at the back of the block (where it extends past the driver’s side) there should be a casting number there. If it happens to be 5.0LG it’s a 305 not a 350.....you’d be surprised how many “350” G bodies turn out to be 305s.

I know I can sound a bit cynical, but I’ve been around this stuff for a long time and seen a lot of cars/engines that are not quite as advertised when you get into them.

X2

Chech the rear frame rail, run you hand up and under, feel were the body bolts to the frame from the wheel back, and feel for puddy in the rear quarter, I look at over a dozen gbodies in the Pittsburgh area and only a few had good frames and ok bodies that people wanted a fortune for so be careful. I asked if the had good frames and I was always told yes, they either don't know or are looking for a sucker. So just be careful. The serpentine belt is fine, until you make 600+, even then it's just a matter of choice I wouldn't but some swear by them.

 

[WiCK3D_SiX]

I asked for casting or part numbers to verify the build. He said he doesn't have any receipts as it was a " back yard build" but does have proof of the block, and mileage. As long as that much checks out I don't think I'm going to worry to much. A 5.7 is still a good starting point either way. He said he's only getting about 5 mpg so I'm guessing he's either a lead foot, or it needs a good tune up.

 

[Mike P]

".... but does have proof of the block, and mileage....."

I'm going to take a guess here and say he's probably got a receipt/warranty paperwork for a rebuilt short block. That could be either good or bad depending on who the actual rebuilder was.

In the case of the low cost short blocks you can buy from some of the auto chain stores, the short block is usually rebuilt with the cheapest parts they can find and usually automatically bored .060 over and the cranks turned to .030 under (the maximum you can overbore and turn a crank). The rebuilder does this so he only has to stock one size of pistons, rings and bearings which they buy in bulk. Basically the engine is all used up as far as any future rebuilds. The cams are usually a mild stock grind (probably in the .430-450 lift area).

IF it is a box store rebuild, as is, the short block might make the basis for a
decent grocery getter engine but it is definitely not something you want to use power adders on.

I'd also verify that they did not just throw a set of small chamber 305 heads on the 350 short block (may require pulling the valve cover and running the casting number). If they did use small chamber 305 heads there is a good possibility the compression is up around 10:1 or possibly more (too high for pump gas, stock cam and small port heads).

Again this is a SWAG here,...... but worst case scenario is it’s a cheap rebuilt short block with the stock 305 heads, small cam, intake ports and valves, a grossly mismatched intake and too much compression. In that case the timing would be set way retarded to prevent detonation, it would run like crap and get oh about 5 MPG. Unfortunately a good tune up isn’t going to help it.

I could be completely wrong..... I’m just saying check everything possible. As far as how do I know how a combination like this runs? We had a customer bring a trash can engine like this several years ago....we made it run, but it took some parts swapping (heads and intake).