Hi all. I've got a 300hp crate motor(pre-vortec heads)with about 15000 miles,and was thinking about putting it in my 89 formula 350. After reading postings here,I know that I will not have the same hp with the tpi as I have with the carb.I'm really more interested in what kind of torque I can expect from this crate motor in my car. On another track,I'm thinking about some minor mods while I have the crate motor out and accessible.Like a lingenfelter cam with roller setup,and maybe an intake change(or porting). Any thoughts/ideas are appreciated. thanks p.s.-here's a spec page for the 300hp crate- http://www.sallee-chevrolet.com/Chev...ckV8s/300.html 89 formula 350,3.27,auto,dual exh.

 

Looks like the motor put down a lot of torque, 300 ft lbs @ 1750 rpm. If you did a cam swap it might go down a little (depending on the size of the cam) but if the cam's smaller it will go up. If you ported the heads and intake and added a mild cam you could hit 380hp and 400 ft. lb of torque.

 

Thanks for the suggestions,kfoley. I've been reading here for a few months trying to get a better understanding of engine components in relationship to performance.I've yet to really wrap my brain around it,but I figured a cam change would be a fairly simple way to modify this motor. I didn't think these heads would be very good for modifying,but I will like it if porting them will give even a little better flow,without spending too much on them.I thought of just getting the vortec heads,but with the intake I would need,that's 8 or 900.I would rather spend half that on some porting and a change to roller lifters. On the camshaft:did you mean smaller than the .435/.460 it is now,or smaller than a high lift camshaft(+.500)? Thanks again,cam

 

A cam swap will make a big difference in power output and it'll pull harder on the topend. You can port the heads yourself, it's not that hard, if they're low mileage you can port them, clean em up real good and slap them back on the motor w/o any machine work being done. Do a search for Fbird-88 and Sitting Bull, they have good posts about porting heads that will help. If you're wanting to change to roller lifters, it's not going to be cheap. The cam alone is $300 plus another $300 for retrofit lifters (needed unless you have an '87+ roller block) and you need a cam button and decent timing cover and timing chain set (it has to have a thrust bearing), so you're looking at about $700 to switch to a roller cam. Spend that same amount of money on a set of Vortec's, rpm intake and a good hydraulic cam and you'll be much happier. The head combo will put you at 400+hp, whereas the roller cam setup and porting the heads will give you 50 or so hp. The cam that is in there not sounds like a 214/220 duration cam. If you went smaller tq curve would shift back and the hp curve would fall. If you went a little bigger (say XE268, 224/230 dur) both curves would go up, now if you went even bigger than that (not suggested w/tpi) like the 274 or 284, the hp would go up substantially, but tq would suffer on the low end. Hopefully this hasn't been too confusing for you, I tried to keep it kind of vague, but if you would like a full explanation of cams and such just let me know.

 

Somewhat. I need to read more on camshafts to get a better understanding. I would probably be happy with the motor as is,if I don't lose any torque.From reading here,I'll lose about 50 hp,but I'm hoping with the tpi I might pick up a little more torque. I feel like I'll be wasting a good opportunity if I don't do anything while I have the chance,though. I was thinking if I changed the heads,I might go to the fastburns. The vortec heads by themselves add hp,but not torque.And if I'm going as far as changing the heads,the fastburns are only a few hundred extra.

 

The Vortec's will give you more hp and tq. The fastburns will give you about 20 more hp than the vortecs (and tq), plus the fact that they're aluminum will be a weight advantage. However the vortecs can be bought cheaper off ebay ($500 or less) and I personally don't think the extra $300 is worth it for 20 extra ponies, but that's just my opinion.

 

I appreciate it. I hadn't looked at the specs on the 330hp crate engine for a long time.I thought for sure the peak torque #'s were the same,but the vortec is a little higher. here's a page on that engine- http://www.sallee-chevrolet.com/Chev...ckV8s/330.html The thing I don't like about the torque curve with the vortec's is that it's not as smooth as the curve with the iron heads. That's with a carb,though,and I'm guessing that tpi on this crate engine(iron heads) will produce a different curve than with the carb. I'm really torn with this.Part of me thinks I should just install the engine,and the other part says don't waste an opportunity and build it up to something special right now. Thanks for the help

 

TPI will flatten out the tq curve... I know what decision you're dealing with, I had the same one, either modding my 305 and waiting to spend money on my real motor (blown 383 btw) or be slow and work on the new one. I decided to lightly mod the 305 after some disappointing times at the track.