98 suburban 383 or not

[frank96hd]

I have a 98 suburban with a 350 vortec and was thinking of making it a 383 using the stock intake setup and ex. manifolds, tune on the pcm and still use the stock lift cam. I can't seem to find anything else on the net about anyone else doing this everything I find they are using carbs. Does any body know anything about this combo? Any info is appreciated, Thanks Frank96hd

[2000CAYukon]

GM Performance Parts makes a HT383 that is 49 state legal (they claim) that uses the stock computer (and does not required to be programmed). However, a custom tune might make even more power.

http://paceperformance.com/index.asp...&ProdID=184746

They list the cam shaft that they use for this engine and the torque numbers very good (435 ft-lbs). You could build a 383 and use the same cam. I think that the stock cam would be too small for the 383. IMHO, cam choice is important here with the longer stroke.

//2000CAYukon

[sub006]

383 crate motors are much more expensive than 350s. Performance and mileage are not that different, unless you need more grunt for towing. A 383 or bigger small block then makes a lot of sense, because the mileage will be much better than with a big block.

If you're machining your existing block and doing the assembly and install yourself, it's not that much more.

[jtmarten]

Originally Posted by sub006

383 crate motors are much more expensive than 350s. Performance and mileage are not that different, unless you need more grunt for towing. A 383 or bigger small block then makes a lot of sense, because the mileage will be much better than with a big block.

If you're machining your existing block and doing the assembly and install yourself, it's not that much more.

How is a 383 significantly more costly than a comparably outfitted 350? Isn't the only difference the 400 crank? Usually the 383s cost more because they're built with performance in mind, using higher $$ internal components, which drives the cost up.

Mileage won't be significantly better than towing with a BB. My 98 K1500 got 14.5 hwy non-towing, 10 towing my 4500lb 23' jetboat. My 96 K2500 w/454 gets 13 hwy non-towing, and 9.5-10 towing my 7000lb, 26' Wellcraft offshore. I'm guessing the K1500 mileage would be significantly lower towing the new, heavier boat.

I doubt there would be any issue bumping to a 383 on a rebuild. The ECU will keep the A/F the same as with the 350, you'll just use a bit more fuel. I doubt you'd even need to tune the ECU if everything else is stock.

[777stickman]

Originally Posted by jtmarten

How is a 383 significantly more costly than a comparably outfitted 350? Isn't the only difference the 400 crank? Usually the 383s cost more because they're built with performance in mind, using higher $$ internal components, which drives the cost up.

There is also machine work involved on a 350 block for clearances associated with the 400 crank and rods that add to the cost.

[wafrederick]

Plus with the crate engine,you get a better warranty.Lot of times,it is not worth rebuilding now since a crate or reman engine have a better warranty. You will get bad new sometimes,machine shop calls you that they found a cracked head for example and this can be more expensive.With a machine shop,do your homework first for one and one is if they do good work standing behind it.Some will not do this not standing behind their work if there is a problem.

[sub006]

Originally Posted by jtmarten

How is a 383 significantly more costly than a comparably outfitted 350? Isn't the only difference the 400 crank? Usually the 383s cost more because they're built with performance in mind, using higher $$ internal components, which drives the cost up.

I just compare the Chevy dealer crate engine prices, Edelbrock's crate prices, etc. Comparable 383s sem to be at least $1000 more than 350s. Maybe they're taking extra profit, or costs are higher because 383s might be 5% (or less) of production compared to 350 volume?