I'm dropping a stock 1986 454 from a Mass. state Police Suburban into my 68 Chevelle. Has anyone ever put 1.8 ratio rockers in a BBC with stock cam? Stock lobe lift is .234"/.253" and I'll be swapping the peanut port heads with stock 1971 "820" large oval heads.
Just check you push rod lengths and rocker alignment. Who brand you running? I had a set of Jesel's on a dirt late model. Worked very well. Had to check the clearance to the head as the push rods got very close to the casting. Of course we were running an aluminum head. It took a little playing with push rod length to get a good contact on the valve tip. Also get a good valve spring.
The big rockers will do the most good on the intake side, thAn both or exhaust only. Experiment with this. Note that you "may" have to increase the spring pressure a little. The rocker is is pushing the valve open just a little farther, but it's doing it faster (a good thing), but it's also dropping faster which is a little harder on parts. Just watch out for valve float (nasty noise's). If that's case, up the spring "seat" load by about 30+lbs. And as 70d says, when ever you change things like this, make sure the rocker tip is still moving across the valve tip properly during the opening and closing events. Mike
I've used stock ratio 1.6 rollers on a 5.0L Ford for the intakes and 1.72 rollers on the exhaust... It did wake the motor up alittle...
Good feedback. That confirms everything I already assumed and always comes into play when considering 1.8 rockers with a modified engine. I'm hoping to get some feedback using the 1.8's in a stock application as a low budget alternative to a cam swap. Think of this 68 as a modern rat rod. It looks good from a distance but it's a daily driver that I rescued from the crusher as a parts car. Threw some paint and parts at it and wahla. If I can't make the parts I have work, I need to use other parts I have laying around or find them on the cheap (free is good). I'd leave the six in there if it were in better shape and got me out of traffic quicker.
Good luck with your 68. Looks nice in the picture. A 454 should move that beast bone stock. Lots o torque
Thanks 70D. For lack of better words - I can really polish a turd. Didn't even need any filler on this one. Could have dropped the FUZZ 454 in as is, but seemed a little boring to me. Got a vintage Edelbrock C396CJ intake out of stock and a free set of 71 heads that started this whole crusade. Top it with a 750 QJet and it's a recipe for a classic sleeper. Way better than the six straight shooter it in now.
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