Tim-
i would go by what AEROSPACE recommends for that model. i have the instruction sheet for mine around if you dont have the pump yet.

Did you get the 350gph ?

Relays should be used to handle the high current lines..
The downside of using a heavy amperage switch is that with every make/break there is a spark.. This spark tends to oxidize its internal contacts and eventually it will build up resistance and fail...
Think about just like a set of ignition points..

Just my $0.01..

certainly no one is suggesting using a switch for starter current that's not a reasonable comparison. nor is anyone suggesting not protecting a circuit that's asking for problems and electrical fires are notoriously hard to extinguish if you don't power down the circuit. imho i use fuses as little as possible, i prefer circuit breakers. they can be had at a reasonable price and fit into a standard ATC fuseblock. there are also different styles of breaker reset. continuous cycle, reset after load disconnect and manual reset.

define "high current", the same arcing that occurs in a switch occurs in a relay. a quality switch will be reliable for many thousands of cycles. most of the "flashy" lighted switches that are so popular are junk as are switches with all plastic bodies. usually quality switches (micro, cole hersee etc.) aren't pretty and flashy, they're also usually not all that cheap. they're plain bat handled switches made of metal and bakelite (or similar). i've done a LOT of wiring over the years including gensets up to 300KW and the number one problem i've seen is poor workmanship which includes low quality materials. poor connections (resistance) result in heat and heat further degrades the connection it's a snowball effect.

i've used hundreds of relays over the years and if you're going to use a relay i'd tend to stick with bosch. years ago we started using potter brumfield and had a higher failure rate than the bosch. as for the chinese/taiwan stuff...if i found new ones in my shop i'd straight up throw them in the trash.

the lines you REALLY want to be careful with are the (imho) "high current" lines...battery and starter lines. they are rarely protected and special attention should be payed to their routing and armor. watch for sharp edges, use loom and grommets where they pass through bulkhead or firewall etc.

I thought about adding relays,
but seeing that picture, I'll
stay with what I have.
Fuses no relays.
Steve

Why is it that most all of the "professional" wiring companies like Speedwire and Spaghetti Menders use relays? I'll stick with my relays!

Mike Gray

Duster Wiring

No relay requires higher quality parts, but also fewer components means fewer failures. NASA would use relays, but also 2 circuits in parallel back to hot with a selector.
Under the car with a wrench playing with current while wet with gas isn't fun.

I use relays to cut down on large "hot" wires to the dash/switch panel.

I have no "hot" wires running to my switch panel. one wire for each switch goes to the relay grd. And I run one ground wire from the battery to a terminal next to the switch panel and attach the other side of the switches to the terminal.

Take Fred's pic and jumper the "switched hot" to the same relay terminal as the "fused hot". and run the ground wire to the switch. Now there is one hot wire running to the relay (fused) and one hot wire running to the load (fan, fuel pump, water pump, etc..), with the ground running to the switch, there are only three wires from the relay.

The relays use about 1/4amp, so a small ground wire can be used and just about any switch can be used with out risk of arc'ing or overheating.

If you run lighted switches, you would only need to run one small hot lead to the switch panel which would power the lights when the switch grounded.

I Have relays on my 69 Bee street car. Relays are used to power the fuel pump, Gearvenders, line lock, and MSD ingition box. All relays are activated by the ignition relay when the key is turned to on. This eliminates having to have switches in side the car to for all these items. Everything is also fused. The relays all take power directly from the battery with a circuit breaker between the battery and the relays. My RED uses a Painless race car wire kit and switch panel with all circuits fused and relayed.

the best relay set up is spaghetti menders, full led and fused.no wires,just connect and go,they have 3,4,5 wired relays,or can custom make,this is what i have.