5.0 to 5.7 engine swap questions

[chrisw21]

My 1999 5.0 is toast (cracked block), so I'm thinking about going to a 5.7 for replacement. Here are my questions:
1) Can I go short block? Are heads, intake, carb, etc. the same?
2) Is the timing curve the same? Can I use my current Thunderbolt ignition or is the 5.7 different than the 5.0?
3) Is the gear ratio in the Alpha the same for both engines?
4) Any other differences I should know about?

If I can make the change for the same amount of money or a few hundred dollars more, I would rather go with the 5.7. I have new heads and complete exhaust for the 5.0 and I would like to use these parts if I can, but if not then I may just buy the long block and try to sell them later. Thanks in advance for the help!!

 

[ryendube]

Re: 5.0 to 5.7 engine swap questions

305 heads have smaller valves 1.72/1.48 to 350 1.94 1.5

combustion chamber is smaller which will increase compression ratio

intake runners are smaller.

all this means is heads will restrict flow in the larger displacement motor and you must take in consideration the compression ratio ie not making iot to huigh with piston combination

 

[Bondo]

Re: 5.0 to 5.7 engine swap questions

Ayuh,... Go with a Long block, not a Short block....
As noted above, you Don't want to keep the Heads...
Questions 2 thru 4 are Non-issues....

 

[chrisw21]

Re: 5.0 to 5.7 engine swap questions

Thanks for the input guys! What about the carb? Its a 2 brl. Were there any 5.7s that came with a 2 brl or were they all 4 brl? I know there were many hp variations offered for the 5.7, so do I need to order a certain version of the 5.7? I'm assuming that the higher hp versions would have a larger cam and require a 4brl carb, but I don't know for sure. Thanks again!!

 

[FreeBeeTony]

Re: 5.0 to 5.7 engine swap questions

If you're thinking of upgrading to a 4bbl which would require a new intake manifold......might as well go with the Vortec heads..........you'll be glad you did. Might be a few extra $$$ but If you don't do it now you may regret it later............

EDIT: just noticed your year was 1999.......so chances are you are already Vortec.......