2 questions

[badfast47]

I have to take my aluminum heads and intake off my 406 with 6 " rods with a roller cam and lifters. Then put the heads and intake on a 350 short block bored 60 over, 6"rods and 400 crank with a solid lift cam. Any guess as to how much hp/tq can be lost between the two ? Also will roller lifters work on a solid lift cam ? ? Thanks for any insight. Just wondering how much i will lose with this switch.

[Confused?]

Don't know about the rest but, you can not use roller lifters on a flat tappet cam. It will kill the lifters and lobes.

[14flower]

you will lose top end tourque 383's start to drop off tq after 6500 rpm idc what parts u use in side it just the way the bore to stroke works out. but your top end rpm u can turn and the snappyness should be a bit better id set down one gear set if u can like for example from a 6.83 to a 7.00 to help with lost hp. btw a intake that works good on a 400 may not work so good on a smaller engine inless rules state u must run that intake

[badfast47]

For got to mention the crank is a scat cast steel crank. It's a back up motor. With the 406 i was using a 6.33. and getting between 7000 to 7500 rpm's. So should i go with a lower gear to make up the difference in HP, keep the same gear or more something like a 5.83 to keep from blowing it up ?? Trying not to go much over the 7000 rpm's. Thanks

[badfast47]

Any thoughts or comments about this at all would help

[tutt71]

The engine cubic inches aren't that much different. The heads and intake are the same. So....The biggest losses are coming from the drop down to the flat tappet cam. You could probably expect about 25-40 less horsepower and 25 less torque. You will have to change the springs on the heads to match the flat tappet cam and no you can NOT put the roller lifters on the flat tappet cam. Anytime you switch any part of the valvetrain you should check piston to valve clearance to make sure everything is compatible.

[badfast47]

In the process of putting in a 600/600 roller cam with the roller lifters. The pistons are flat top so that shouldn't be a issue with the valves. I should notice little more hp by changing that.... I hope