If you're trying to use the internal clock (Fosc/4) for the TMR1 clock source, then you'll need T1CON = %00000001 VS T1CON = %00000011.

You'll also want to place DISABLE just prior to entering your int handler.

With ONINT you can do pretty much whatever you like in the int handler.

You can tinker with this code below. It's tested on a 16F627A @20MHz.
Code:
@ DEVICE HS_OSC,LVP_OFF,WDT_OFF,MCLR_OFF
DEFINE OSC 16 ' Tested at 20
include "modedefs.bas" 'include serout defines

    Loops   VAR WORD ' Loops value
    loops   =   0    ' Start clear
    
    TRISB = %00000010 'All port b output except pin 1 (RX) is input

    INTCON = 0
    PIR1 = $00        ' clear interupt flags

    serout 2, T2400, ["starting", 13, 10] ' Before interrupts are enabled

    TMR1H = $00     ' load timer1 with $00FF
    TMR1L = $FF
    T1CON = %00000001 ' TMR1 on, prescaler=1, clock=(Fosc/4)
    INTCON = $C0    ' Enable global and peripheral interupts
    PIE1 = $01      ' Enable TMR1 overflow interrupt 

    on interrupt goto inthand

loop: ' endless loop with 1 ms pause
    pause 1
    goto loop

    DISABLE
inthand:
    loops = loops + 1 ' increment counter of interrupts
    serout 2, T2400, ["loops = ", #loops, 13, 10]
    TMR1H = $00       ' load timer1 with $00FF
    TMR1L = $FF
    PIR1 = $00        ' clear interrupt flags
    RESUME
    ENABLE

End