FrontEngineDragsters.Org Forum

Technical => Matt Shaff's Engine Shop => Topic started by: grapro on September 30, 2018, 03:28:40 PM

Title: 421 or 434
Post by: grapro on September 30, 2018, 03:28:40 PM
Looking at purchasing a new sbc shortblock from Shafiroff and debating on which one. Have a set of Promaxx 225 heads and my Hilborn stack injection. Have a set of 4.30's in the pumpkin and not sure which way to go. 421 or 434.
Title: Re: 421 or 434
Post by: jeff/21 on September 30, 2018, 03:39:59 PM
Any difference other than size?
Title: Re: 421 or 434
Post by: Paul New on September 30, 2018, 04:02:50 PM
I would ask them which would build more power with the heads you have.  If it’s NA remember the old saying no replacement for displacement
Title: Re: 421 or 434
Post by: wideopen231 on September 30, 2018, 06:57:49 PM
Only reason I can see for buying smaller engine given choice would be if it had smaller bore and could be bored out more later. Other wise go as big as you can afford.