Can I use 5881 tubes in this amp instead of el34?

[newguitarsmell]

https://music-electronics-forum.com/attachment.php?attachmentid=45018&d=1506148051

If I have to mod the filters, what do you guys recommend?

[shooter]

https://frank.pocnet.net/sheets/049/5/5881.pdf

https://frank.pocnet.net/sheets/129/e/EL34.pdf

look over the datasheets, what stands out that bothers ya, me, I wouldn't even unscrew the chassis if it's workin 

[sluckey]

https://music-electronics-forum.com/attachment.php?attachmentid=45018&d=1506148051

If I have to mod the filters, what do you guys recommend?

No need for mods. Just plug 'em in and play it like you stole it.

[VMS]

check bias first then play it like you stole it