Smeding Performance 383 Extreme
 

So I have been Racking my brain for awhile with which crate engine swap should I replace my 307 in my 67 C10 Long bed, Did the internet search, Read alot of comments about different builders, (BTW you can't go by what some people say) So long story short, I just found out about Smeding Performance the other day, Call them today and was pleased with the conversation, I pretty much went with what I knew I needed all along, One change in plan was Carburation, i wanted to stay old school, but knew the benefits of the Holley EFI, So I went with that, Also wanted it to be turn- key, Ordered everything I need for that situation, Put my downpayment in and they will start on the build in three weeks, This will be a brand new GM block, The fact of the matter that they will do the break-in of the engine is a big plus for me.

Re: Smeding Performance 383 Extreme
 

Pretty cool! I have a buddy with a turn-key Smeding 383 in a 55 Chevy car and he loves it.

What transmission, axle ratio, and tire height do you have? If stock, you might be better off with their 383 Cruiser.

Also, are you good to go with a fuel pump and return line for the EFI?

Re: Smeding Performance 383 Extreme
 

...I already put way more money than I thought I was gonna put in this truck, so I was gonna have my stock 350 TH trans gone through, But got lucky and ran into a guy at the shop that had a TCI 350 TH trans ready to go, it could handle an over 600 HP engine, He was selling it for 1000 dollars, I couldn't pass that up, As for my 12 bolt rearend it had a 3.73 in it, went through the rearend and changed it out for an Eaton 3.42. As for my wheels I went with taller rims, 17" and stuck with the 6 lug, tires are 275/60R17. Forgot to ask Smeding Performance about the Fuel pump, I guess I'll give them another call, BTW how many miles does your buddy have on his engine ?

Re: Smeding Performance 383 Extreme
 

Probably no more than a 1000 miles, if that. The car's been finished for only 3 months. I'm not sure which version of the 383 he has, but I'll find out.

I was just saying that the one you ordered may be a bit much on the street. You'll probably want a torque converter with a higher stall speed. If the TH350 comes with a converter, check with TCI to see if it's optimal for your engine. They will probably want to know the camshaft specs at .050" duration.

The truck should be a blast to drive, but even with 30" tires like yours, the engine will be spinning pretty fast at highway speeds with 3.42 gears. I once had a mild 383 in a 69 C10 with a TH350, 29" tires and a 3.08 axle. At anything over 60-65 mph, I was always wishing for a taller rear gear! 3.42 would have been a non-starter for me.

Keep in mind that your 383 will probably make 50% more torque and do it at lower RPM than your old 307, which means it can pull a much taller gear and still accelerate much quicker. Depending on how often you drive at highway speeds, I'd suggest 3.23 maximum.

Re: Smeding Performance 383 Extreme
 

...Yeah, the transmission won't come with a torque cover, I'll call Smeding Performance, It will differently need an over 2000 converter, At the time the rearend had a going through, I wasn't thinking of this much engine, But your right, the 3.42 isn't probably tall enough for this engine when it comes to highway driving, I wonder what RPMs I'll be pulling @ 70 mph

Re: Smeding Performance 383 Extreme
 

Here are some calculations to determine RPM at road speed based on tire height and axle ratio. Use the one you like best.

http://www.wallaceracing.com/calc-gear-tire-rpm-mph.php

http://www.advanced-ev.com/Calculators/TireSize/

https://www.reillymotorsports.com/sp...alculator.html