mrtater99

iTrader: (1)

I've been slowly workin on my 350 build when time permits. I have a 92 block out of a cop car that I ended up using, because the other block I had, ate a piston, completely..It also cracked the cylinder wall. Anyway what I have so far is a LT4 hotcam and springs, a tpi with the base opened 2" between the runners, 58mm BBK. 1.6 full roller rockers, and a set of twr domed pistons, with 4 reliefs in the dish. I was going to port and polish the swirl ports at my machinests suggestion, but found both of them are cracked. I picked up a set of 487's a while back that are in good shape, that are ready to port, but he tells me that they dont flow as good as the swirl ports on the bottom end. What I'm after is a good street motor with an attitude and the abuility to win against the occasional mustang. 400 horse would do fine. I also have the lateset megasquirt. V~3 with map daddy. This will be my second ms install. I've been checking the web looking for flow numbers and have only found conflicting answers about how good the 487's are. My question is, how would these heads, pistons, work with the hot cam? The cam, tpi, and ms stay, the rest can be changed. Any suggestions for this build. The block is at the shop getting cleaned and prep'd. Pistons, 487's and cam are on the shelf waiting for decision. I found alum. heads on ebay for about 650. I was thinking about but haven't found any info on those heads. Procomps 220cfm, 2.02/1.6, 64cc. Also, money is a factor. That's part of the reason it's taking so long. Thanks

mrtater

Atilla the Fun

Swirl-port heads will not get you 300 horses, let alone 400. Domed pistons are also old tech. They just add weight where you don't want it, add to the cost of getting the crank balanced, limit your rpm range before stretching a rod bolt or worse, and impede flame travel. Flattops and slight milling of iron 76cc heads will get you 9.5:1. 64cc heads with flattops will get you above 10.3:1.
220cc heads are not right for a 350 with the LT4 HOT cam.

mrtater99

iTrader: (1)

Thank you for the reply. If the 220cfm heads are wrong for the LT4 cam, what would you suggest? The 487 heads are 76cc, from what I can tell, but don't know about the flow.

mrtater

Atilla the Fun

the cam is fine. Heads are your issue. A 220cc head is sized large enough that, if it flows as well as a 220cc port should, will feed a 350 through 7000 rpm. It won't really start working until it struggles past 3000 rpm. If that's what you want, you'll need a forged crank, 4340 rods, lightweight pistons with tool steel wrist pins, a solid-lifter valvetrain, a TPIS Mini-Ram, and a 4.56:1 rear gear. The lt4 hot cam will get you 400 horses (at 5600 rpm, and 428 ft-lbs @ 4200 rpm, with 385 ft-lbs from 2600-5400 rpm) with nothing more exotic than a pair of Vortec 350 heads, if you go with an RPMAirGap. If you stay TPI, but get Edelbrock's base and runners, you're looking at more like 360 horses. Don't try this with domed pistons.